PROBID Estimating and Tendering System
PROBILL Contract Billing and Variation Management System
PROVAL Job Valuation and Subcontract Liability
PROCOST Job Costing and Materials Reconciliation
PROPLAN Planning and Scheduling System


Contact
Home

FREQUENTLY ASKED QUESTIONS

This FAQ page contains answers to common questions, along with some tips and tricks in customising and using PROBID, PROBILL, and PROPLAN (including the built-in NOTEPAD and PROCALC tools). You may find these useful.

Note: We use a few shorthand conventions for describing user-interface procedures. Key combinations are presented like this: [Ctrl][End], which means you should press and hold down the Control key and the End key at the same time. Menu selections are presented like this: Master, New, which means that you should go to the Master menu, and select New.

General

  1. How do I search for text in descriptions?
  2. Why doesn't my printer produce any output?
  3. Why does my printer produce garbage?
  4. What are Hyperkeys?
  5. What is "Gestalt Pattern Matching"?
  6. What is the JOTTER?
  7. What is a "User Defined List"?

Customization

  1. How do I change the program's Data Directory?
  2. How do I change the Report Header?
  3. Should I change the Printer port?
  4. Why do I get comma separators in numbers?
  5. Why can't I input dates like 23/10/02?
  6. How do I customise the program for different users?

NOTEPAD

  1. What is a "private" line?
  2. How do I create a NOTEPAD template?

PROCALC - Arithmetic Expression Parser

  1. Why isn't my calc sheet saved?
  2. How do I use variables?
  3. What is the point of templates?
  4. What is the "command line" version of PROCALC?

PROBID - Estimating & Tendering System

  1. How do I "unlink" linked Items?
  2. How do I clone just Operations?
  3. What happens when a Set is expanded?
  4. Can I use different Cost Types for different jobs?
  5. How should I handle Tender alternatives?
  6. Why should I round Tender Rates?
  7. What is "Quantity Loading"?
  8. What is "Front Loading"?
  9. How should I handle Provisional Items?
  10. What is a TOKEN Item?
  11. What are "Special Groups"?
  12. What are Auto Library Batchfiles?

PROBILL - Contract Billing System

  1. My reports show some items out of order? Why?
  2. Do I need both Groups & Sections?
  3. What is a DEPARTMENT SUMMARY?
  4. What are " Special Certificate Groups"?

PROPLAN - Project Scheduling System

  1. What is a Hammock?
  2. What is a "Control Activity"?
  3. Are PROPLAN and PROBID Resources similar?
  4. How do PROPLAN and PROBID work together?
  5. Is PERT COST a useful costing system?
Back to Top

How do I search for text in descriptions?

You can perform a complete Gestalt search on both the codes and descriptions contained in any picklist. When the picklist is on the screen, hit [F5], and type a fragment of code - or text - into the input field that appears below the list.

Press [Enter] to start the search from the first record in the list, or [F5] to start at the next record- the one following the current picklist highlight. The highlight jumps to the "best matching" record. Text you enter in this field remains as a default while the picklist is active - so [F5][F5] effectively repeats the search for further records.

As with "loose" masks - or Find and Replace - a fragment that is all lowercase matches case insensitively while mixed or uppercase search text matches case sensitively. [F4] will copy the highlighted record into the input field so you can edit its text to create a starting search fragment.

Back to Top

Why doesn't my printer produce any output?

If you are printing under a Windows network, you may not have properly configured the printer  so that it is recognized. (See Printing from DOS Versions of PROBID, PROBILL, and PROPLAN running under Windows 95/98/ME/NT/2000/XP)

Back to Top

Why does my printer produce garbage?

You may have the wrong Printer type selected in Customisation. Select Master, Customisation, Printer Setup and check to see that the Laser Printer? setting is appropriate. If you are using a Dot Matrix printer, make sure that the correct model - or a suitable emulation is set. Also check that your printer's DIP switches are set to produce that emulation.

Back to Top

What are Hyperkeys?

Most editing is performed within the confines of a single screen. Normal movement between these "screens" can take several keystrokes.

The "Hyperkeys" [Ctrl][PgDn] and [Ctrl][PgUp] move directly between logically sequential screens (e.g., the various Customisation screens).

For example, [Ctrl][PgDn], from the Customisation, Printer Setup screen in PROPLAN, displays the Report Symbols screen. [Ctrl][PgDn] again moves to the Country Setup screen. If pressed again it displays the Screen Colors screen- and so on. (Similarly, [Ctrl][PgDn] from the Activity entry screen displays the Link Entry screen- as would [Alt][L].)

Once in the screens, [Ctrl][PgUp] will move in the reverse direction.

[Ctrl][PgUp] is like a "big" [Esc]ape key.
[Ctrl][PgDn] is like a "big" [Enter] key.

Back to Top

What is "Gestalt Pattern Matching"?

A Gestalt or "Intelligent Pattern Matching" facility resolves ambiguities created by partial, ambiguous or erroneous entry. If user input does not exactly match any one of a set of valid choices, the program intelligently evaluates the field and finds the "best" match available - bearing in mind the relative likelihood of different typographical errors and omissions.

This allows you to enter part of a code, press [F5], and have the program find the best record match for that code.

Back to Top

What is the JOTTER?

The JOTTER is a special form of the NOTEPAD. The notes are not associated with any particular record but with the whole job - if one is being worked on. Otherwise they associate with the program installation itself.

The JOTTER is a convenient way to create lists of "things to do", or record quick notes from a telephone call. It is accessed with [Alt][J] or [Shift][F11].

Back to Top

What is a "User Defined List"?

You can create - and maintain - a personal User Defined list of choices for many data fields. If a field usually contains one of a limited set of options, this can greatly speed data entry.

One example; if you frequently create jobs for several different departments you will be repeatedly changing the name in the Job details screen. You can add these details to a file, by pressing [Shift][F6] from the name field.

When creating the next job you can hit [F6] - the SELECT key - to popup a picklist of all the records in this file. Select a particular department and the name will be copied into the field.

Another example; if you always use the same standard Measure Units, it may speed up entry - and improve consistency in the use of abbreviations - if you develop a user defined picklist. After entering a item, task or resource measure unit, press [Shift][F6] to add it to - or amend it in - a picklist.

Back to Top

Customisation

How do I change the program's Data Directory?

From Master menu, Customisation, Directories, just amend the directory name and save the change with [F2].

Back to Top

How do I change the Report Header?

From Master menu, Customisation, Printer Setup, change the standard Report Header and save the change with [F2].

The program will automatically center the heading as it is saved.

Back to Top

Should I change the Printer port?

PRN is the default output device. This "logical" MS-DOS device normally refers to a printer - regardless of how it is connected. With the device set to PRN, the program uses BIOS sensing for immediate feedback on print errors. Screens and defaults then respond and adjust dynamically to the printer status.

If you want to switch between two simultaneously connected printers - or have problems printing to PRN - you can set this field to refer directly to a physical port. BIOS sensing is then disabled.

When printing over a Local Area Network (LAN), it is generally better to leave the device setting on PRN and handle all port redirection at the LAN level.

Back to Top

Why do I get comma separators in numbers?

A Thousands Separator for numeric values may be specified through Master menu, Customisation, Country Setup. This separator is used to format the output of large numeric values. (Separators may also be entered in most numeric fields. However, to simplify editing, their position is not interactively validated and they are replaced by spaces before the field is saved.) 

If a derived value is too wide to display, the program first tries to fit it into the space available by suppressing thousands separators. If the result is still too wide then the number of displayed decimal places is reduced. If the number is still too big, an overflow indicator and an error message is shown.

Back to Top

Why can't I input dates like 23/10/02?

Dates may be input in:-

 international ddMMMyy format (e.g., 23Oct02),

numeric format s - DMY, MDY or YMD

or relative format (+ or - days from the system date.)

Regardless of the entry mode - or country settings - dates always appear in international ddMMMyy format.

The numeric format setting is controlled from Customisation, Country Setup.

Back to Top

How do I customise the program for different users?

Your choices from all the Customisation screens are saved in a Customisation Template file in the system directory.

The program allows you to save and access multiple customisation templates. These files all have a CTL extension and are saved in the system directory.

Additional CTL files can be created by keying [Alt][S]ave from any of the customisation screens. A picklist of existing files appears - with an option to create a New File. An existing template can be re-activated with [Alt][R]estore. It then remains current unless you switch to another job.

Jobs are associated with their own template - the one active when it was created or last saved. When you switch to another job, it automatically restores its own customisation template. This means you can associate sets of jobs (different departments, types of work, etc.) with different templates. The program then re-configures itself automatically as you switch jobs.

When a customisation file other than the default file DEFAULT.CTL is being used, the customisation screen headers show the base name of the file.

Back to Top

NOTEPAD

What is a "private" line?

A vertical bar character "|" used in the first position on a NOTEPAD or PROCALC line produces a "private line" - effectively a comment that will not be included in reports.

Back to Top

How do I create a NOTEPAD template?

In addition to associating NOTEPAD details with particular records, you may save notes in separate template files.

[Alt][S]ave copies the current NOTEPAD to a file in the system directory. [Alt][R]estore reads files back into the NOTEPAD.

The Save and Restore commands provide a convenient way to transfer text between records - even in different jobs - and between the NOTEPAD and word processors.

[Alt][S]ave produces a picklist of existing "templates" and allows you to add new ones.

[Alt][R]estore reads templates saved with [Alt][S]ave or, in fact, any text file with an ASC extension in the system directory. If just one ASC file exists, [Alt][R]estore reads it. If there are multiple ASC files, [Alt][R]estore produces a picklist to allow you to select one. Hence, you can create a number of templates - such as pro-forma Qualification letters, Work Orders, etc., and quickly select one to import into the NOTEPAD or JOTTER.

Back to Top

PROCALC - Arithmetic Expression Parser

Why isn't my calc sheet saved?

Probably because you are not exiting correctly or you have accessed the system version of PROCALC.

PROCALC can be accessed in two different ways.

[Alt][=] calls a system version from anywhere within the program.

On the other hand, if the cursor is in a numeric field, (quantity, usage rate, production rate, unit rate, markup percentage, etc.), a field specific version may be called with [Alt][C].

If the calculation is completed with [Alt][C], or [F2], the formula is saved and linked to the parent field. It can be re-accessed from that same field at any time. You retain not only the calculated value but also the formula which produced that value.

Back to Top

How do I use variables?

PROCALC allows you to use single character User Defined Variables. For example:-

R=2.5+750/1000: A=1.5    ;R is now 3.25, A is 1.5
C = A + R : A=a + 5     
;C is 4.75, A is now 6.5
4 * C/10 + A            
;line value is 8.40
r=10 : h=20 :R x H/2    
;line value is 100

A variable value set on one line can be used on subsequent lines.

Back to Top

What is the point of templates?

They facilitate reuse of standard calculations, tables of values etc., - saving time and avoiding mistakes.

You can save a calculation sheet with [Alt][S]ave and the saved lines can be brought back into PROCALC with [Alt][R]estore. ([Alt][S]ave and [Alt][R]estore work in much the same way in PROCALC, the NOTEPAD  and the JOTTER.)

The file extension for PROCALC template files is PCL. (The extension for the NOTEPAD and JOTTER files is ASC.)

([Alt][R]estore will also read externally prepared text files with these extensions back into either PROCALC or the NOTEPAD-JOTTER.) Hence, you can create and reuse multiple calculation templates that are independent of a particular job. These could be complete conversion charts for weights of steel sections or reinforcing bar, or standard trench cross section areas, or a "spreadsheet" for calculating an "all in" labour rate from basic award provisions.

Back to Top

What is the "command line" version of PROCALC?

The command line version of PROCALC is a stand alone program that can be run from the MS-DOS command line.

Most facilities and functions in the command line version of the PROCALC freeform arithmetic expression evaluator, parallel those in the integrated version. However, there are some necessary differences.

This version can be passed a command line expression to evaluate, e.g.,
   
PROCALC 43.5 + 2 * 23.5/(7.8 + 2.1)  yields 48.25.

If no command line is provided it operates interactively and continues evaluating expressions typed in until there is no further input. It then shows a grand total for all the entries.

Input and output can be redirected in the normal way. Hence:-
   
PROCALC (234.7+176.2)/44 > PRN will print the results, and
   
PROCALC < TAKEOFF.LST will read the file TAKEOFF.LST and evaluate each line in the file as an arithmetic expression.

Much like an adding machine. PROCALC has the equivalent of a "paper tape" as all input and output is written to a text file PROCALC.LOG.

If you are running PROCALC from a Windows DOS box, the input and output is copied to the Windows clipboard so that the calculation details can be pasted into other programs.

  PROCALC ? - or PROCALC /H - from the command line will produce a brief description of the program's syntax and list the built-in functions. (In interactive mode, typing ? displays all user defined variables.

    PROCALC /A  will display a PC-8 extended ASCII character chart.

Back to Top

PROBID - Estimating & Tendering System

How do I "unlink" linked Items?

Linking is most commonly done when estimate items are cloned from the Utility menu. If you clone - and link - a number of items you may subsequently find that some of these items should not have been linked as they do not really cover the same type of work as their parent item. (An item may be linked to another so they share the same operations. Pricing one item effectively prices the whole family of items!)

You can Link - and "unlink" - individual items with [Alt][L] from the Item entry screen. Fields appear at the bottom of the screen for the group, section, and item code of the target item to which you wish to link. (The item shown as a default link target is PROBID's best "guess" based on code similarity.)

Amend the code - or use [F6] (or [F7]-[F8]) - to find the correct item.

Back to Top

How do I clone just Operations?

From Change Operations mode, with the cursor in the description field, [Alt][D]elete and [Alt][I]nsert act on operations as if they were a visible list of similar fields. Deletions are saved in a "Cut" buffer and insertions "Paste" from that buffer. Hence [Alt][D]elete, followed by a number of [Alt][I]nserts, quickly "clones" the current operation.

The technique may also be used to copy an operation from one item to another.

Back to Top

What happens when a Set is expanded?

Using sets - rather than having to redefine the same crews and "assemblies" every time they are required to price an operation - saves time and avoids mistakes of omission.

This capability should be used to "automate" the production of tenders as much as possible. If you have a number of sets differing from each other only slightly (e.g., pipe laying crews varying only by the size of the excavator) they can be created very quickly by cloning records and editing.

However, there are times when a set needs to be used - but its makeup changed slightly - just for one particular operation or item.

If a set is entered in a code field in the operation pricing screen, you can "expand" or "explode" that set into its constituent resources, sets, and subcontractors, with [Alt][E]xpand.

The set code is replaced by the first element of the set, and so on progressively down the screen.

If a set quantity has been specified, the element quantities etc., are computed using the set quantity and the element usage rates. The element pricing mode generally mirrors the original set.

Expanding the set is then equivalent to directly entering each element in the proportion in which it is contained in the set.

Back to Top

Can I use different Cost Types for different jobs?

Customisation templates cover all customisation screens so [Alt][R]estoring a template file resets all customisation choices - including Cost Types.

You can save any number of template files and switch between them. Different users can have their own file to personally configure PROBID, or a single user could have files for different regions, types of work (Civil, Mechanical, Building, etc.), printers, or whatever.

When it is first run, PROBID creates a default customisation template file - DEFAULT.CTL - in the system directory.

To create additional template files, hit [Alt][S]ave from any of the Customisation screens. Enter a filename when prompted. Customisation template files are automatically given a CTL extension. [Alt][R]estore - from any Customisation screen - pops up a picklist of these CTL files so you can switch configurations.

Each job "remembers" the Customisation file with which it was last associated. When the job is opened again it automatically re-reads that template file and reconfigures PROBID accordingly.

PROBID will then respond automatically, as you switch from estimate to estimate, to ensure that the Customisation defaults are correctly reset for each different category of job.

Back to Top

How should I handle Tender alternatives?

Estimate libraries offer the most flexible way of handling alternatives in either the estimate or the tender.

Placing the alternative resources - and/or items - in job specific libraries, means you can maintain one estimate and still bring those records back into the job when you want to present - or consider - a particular alternative.

The other approach - creating several different estimates by copying - should be avoided. It may become difficult to maintain the common portions of each estimate, if the alternatives represent only a small proportion of the total tender.

Back to Top

Why should I round tender rates?

A common criticism of a computer prepared tender is:-
   
"it looks as if it has been prepared by a computer".

This remark is usually provoked by ineffective (or even non-existent) numeric rate rounding procedures which produce too many unnecessary and non-significant digits in submitted rates and extensions.

The criticism reflects more than just a concern with presentation. To ease contract administration, and to disguise the estimate makeup, unit rates should be properly rounded.

"Raw" tender rates can convey too much information on the Contractor's estimate makeup - and markup - to competitors, sub-contractors and Owners.

PROBID has sophisticated options for intelligently rounding rates, amounts, and tender totals. It mimics the manner in which a conscientious estimator manually rounds submitted rates - without risk of error and without the tedium of chasing "balances" to produce the required tender total.

Back to Top

What is "Quantity Loading"?

If a tender item's contract quantity is known to be significantly wrong, a tenderer should - at least - take "defensive" action to protect his recovery of overhead and other indirect costs.

If the contract is remeasurable (i.e. a "Schedule of Rates" or "Unit Price" contract) PROBID allows you to easily protect yourself - and even take advantage of the error.

Entering different contract and actual quantities ensures that your estimate is "correct" - you are fully protected from loss of indirects and overheads.

By appropriately "fixing" and "loading" the submitted item rate you can actually take advantage of the error.

"Under billed" items can have their rates pegged higher than the normal direct cost, plus a proportional share of indirect costs and markup.

"Over billed" items can - conversely - be set lower.

To do so, define the item as a FIXED type and manually fix a unit rate or percentage spread.

If the contract is "Lump Sum" (i.e., there is no payment adjustment for changes in quantities) you cannot overcome the problem by entering different contract and actual quantities. The contract quantity itself must be corrected or, if this is not possible, it must be converted to the correct quantity at the operation level.

PROBID's tender analysis sheet clarifies these complications with a tabulation showing the difference between nominal (contract quantity based) and actual markup.

Of course, you must be aware of the risks and contractual limitations on unit rate loading. Owners frown on the practice and may not accept obviously "unbalanced" tenders. Design, or "scope of work", changes can alter the actual quantities - perhaps even reversing the original imbalance. When the actual quantity differs from the contract quantity by more than a specified percentage, some contracts allow for "appropriate" adjustment of the unit rates (although the adjustment is usually based on the original unit rate and so does not fully remove the advantage gained by "loading").

See also Front Loading.

Back to Top

What is "Front Loading"?

Long term projects have significant cash flow implications for the Contractor. One way of improving cash flow, without affecting overall contract value, is to "move" revenue from items executed late in the project to those executed - and paid for - early.

PROBID's facility for setting items as FIXED or MARKED, makes selectively "loading" a tender extremely easy.

This "front" loading can conflict with the need to "quantity" load items - in which case the latter normally takes precedence.

"Front" loading is subject to the same hazards for the Contractor as quantity or rate loading.

Back to Top

How should I handle Provisional Items?

When a tender contains "write in" or "provisional" items with arbitrary quantities - or items that may be deleted from the contract before it is completed - you should define them as TOKEN items.

This protects you in two ways. No markup or other spread is assigned to the items and, when percentage markups are calculated, their value is not considered part of the cost base.

Alternatively, if you are confident that the quantity is over or under assessed, you may consider an appropriate "quantity loading".

Back to Top

What is a TOKEN Item?

TOKEN items appear in the tender with submitted rates and amounts equal to their direct costs. They are also excluded from the cost base when calculating percentage markups.

They are "artificial" tender items - i.e., items that do not represent real work; or are not likely to proceed in their present form; or are not of financial interest to the tenderer. Typical examples:-

"Write In" allowances defined in the documents.
"Nominated Subcontract" amounts specified in the documents.
Provisional items unlikely to be used.
Work performed by other divisions of the company (when the quoted "cost" already includes markup, so it is unnecessary to mark it up again).
Back to Top

What are "Special Groups"?

PROBID allows you to use a special script file to specify that the cost totals - and percentage cost contribution - from particular groups, is to be summarized in a table at the end of the item and operation unitcost reports.

This is a convenient way to show the percentage cost contribution from Site Overheads, Head Office charges, Contingencies, Commissions, Provisional Work, etc.

This text file, UNITCOST.GPS, is just a list of the group codes - or code masks covering a set of groups - to be shown in the tabulation. No special header lines are required. The first two characters on each line are interpreted as a group code or mask.

The file must be in the system directory.

A Total Cost will be shown for any group defined in both the script file and the estimate.

Back to Top

What are Auto Library Batchfiles?

You can automate the process of copying selected library records into new estimates with special "batch" files. These must be plain ASCII text files with an extension ALB.

They can be prepared with a word processor, text editor, or the JOTTER.

PROBID checks for ALB files when a new estimate is created. If no ALB files exist, it proceeds as normal - so the casual user need not be familiar with, or even aware of, the facility. If just one ALB file is found, it is automatically read and the specified libraries accessed. If more than one is found, a picklist appears for you to choose the appropriate file.

Each active line in the file specifies a source library file and a full selection mask. Comments may be created with semicolons - or by enclosing text in braces or square brackets, as in PROCALC.

Back to Top

PROBILL - Contract Billing System

My reports show some items out of order? Why?

When group, section, and item codes are being assigned, their sorting order must be considered. Characters are position and case significant and so their ASCII value fixes their ranking. For the common characters, this order is:-

Blank spaces
Numbers (0-9)
Upper case letters (A-Z)
Lower case letters (a-z)

Pre-planning of group, section, and item codes is vital to ensure that items sort in an appropriate way. Nevertheless, if the coding of the groups, sections, or items-or suppliers, sets, or resources - turns out to be unsuitable, you may be able to change it "en-masse" through the Utility menu, Find and replace option.

Of course, you can choose not to sort reports - but then group and section subtotals will not be given.

Back to Top

Do I need both Groups & Sections?

If a contract contains only a few items, the group and/or section division may be skipped - just leave the codes and descriptions blank.

At the other extreme, a large number of items may be organized into a two level hierarchy - perhaps "Bills" and trade sections within the Bills, or "areas" and work classifications by area, etc.

PROBILL and PROBID's group and section structure can parallel the organisation of any single or double level item subtotaling scheme.

A section has an alphanumeric code and a description. In turn, sections may be classified into groups.

Item codes must be unique within a section and section codes unique within a group.

Back to Top

What is a DEPARTMENT SUMMARY?

The DEPARTMENT SUMMARY is a multi-job report. It includes all jobs in the PROBILL data directory, with the same department code as the current job.

Each job is summarized on one line and department totals are shown. This may be useful on a large project broken down into many subcontracts - or to provide an overview of all jobs administered by one department of a larger organisation.

If all department codes are blank, all jobs belong to the same "department" and are included in the report.

Back to Top

What are Special Certificate Groups?

PROBILL allows you to use a script file to specify that certain groups are to be shown in a tabular summary in the body of the Progress Payment Certificate.

It might, for example, be used to specifically list the totals payable for Variations, Dayworks, Escalation, and Materials on Site.

This text file is just a list of the group codes - or code masks covering a set of groups - to be shown in the tabulation. No special header lines are required. The first two characters on each line are interpreted as a group code or mask. The file must be in the system directory. An amount todate will be shown for any group defined in both the script file and the contract.

Back to Top

PROPLAN - Project Scheduling System

What is a Hammock?

Hammocks represent a portion of a network. They are defined in a similar way to activities, except that:-

No Calendar is specified - it is always the System calendar.
No Duration is specified - it is calculated during processing.
No predecessors are entered - the hammock "hangs" from its Start and Finish activities.

You must give the hammock a code and a description and may, if you wish, also assign selectcodes and milestone dates. The scope of the hammock is given by specifying a Start and Finish activity.

The hammock's duration, dates and floats are all calculated from the dates of its Start and Finish activities. (The duration and float will be in calendar days - not working days - even if the spanned activities happen to have a common work calendar.)

Hammock definition is completely flexible - the "constituent" activities need only form a loose grouping - therefore you should ensure that your choice of start and finish activities makes sense.

Back to Top

What is a "Control Activity"?

Many "real world" projects - particularly "linear" construction like highway, railway or pipeline work - consist of several loosely related mini-projects that could proceed in parallel if unlimited resources were available, (e.g. earthworks between mass haul points of balance.)

Much of the constraint in the schedule is, in reality, the economic one of providing reasonable levels of equipment, labour or supervision, at any one time.

This problem can be addressed with the techniques of resource constrained scheduling, or resource leveling. However there are serious practical difficulties in implementing either of these approaches and computer models will always produce results which are sub-optimal and do not reflect the complexities of real projects.

A more realistic analysis is often possible if "control" activities are used.

A "control" activity is defined covering the total amount of each work type (e.g. asphalt paving) embodied in the separate activities from the "mini-projects".

The duration of the control activity is the total duration for that type of work given reasonable and "economic" resource levels. The individual activities are linked to the control with Finish links of zero lag.

The effect within the network is to make the control activity critical while the individual activities "float" within the span of the control. (It may not be important to be paving in any one area of the job, as long as paving is underway at maximum output in some location.)

A sequence of control activities can themselves be linked with appropriate logical links and lags.

This produces a much more realistic network model that recognizes the multiple resource constraints without suppressing the inherent real flexibility that exists in the way individual activities and areas of the project can be worked.

The Project Manager is able to exercise his judgment in assigning priorities within this overall framework. That judgment will reflect his explicit - or intuitive - assessment of complex issues such as resource substitution, the "costs" of idle or poorly utilized resources, uncertainty in duration and productivity estimates, the relative importance of certain tasks - as well as the risk associated with delaying those tasks - in a way that still defies computer modeling.

Back to Top

Are PROPLAN and PROBID Resources similar?

While superficially similar (they both have codes, descriptions, costs, etc.) the resources used in PROPLAN and PROBID also differ in several respects.

PROPLAN resources are Reusable (e.g. carpenters, bulldozers, power demand, systems analysts, office occupancy, batching capacity) or Consumable (e.g. bricks, concrete, cash, energy consumption, computer time.)

PROPLAN resources also have an allocation mode. This may Daily usage, Fixed amount, or Start or End day.

The allocation mode allows you to distinguish between resources whose consumption is dependent upon duration and those whose consumption is fixed.

The latter can be allocated as total amounts in three different ways - as a "Fixed" allocation, which the program will evenly spread over the activity duration, or totally on the Start or End day.

The default is by a Daily usage rate. This may be appropriate for labour, equipment and supervision if the work force is constant - and hence the total usage varies with task duration. This is common where a fixed crew is assigned to a task and the duration depends upon its productivity.

If the total consumption of a resource depends upon the physical amount of work to be done, and is not directly related to the time taken, the allocation mode should be by "Fixed" amounts.

This is typically the case with materials such as bricks and structural steel. It may also be true with labour or plant if the productivity rates are reliable and the time taken depends only on the number of men or pieces of equipment assigned to the job (often the case with jobs like bricklaying, steel erection, welding, or ripping.)

For Fixed resources PROPLAN spreads the total amount allocated to a task over its duration. Special allocation modes can be specified if the demand for a resource occurs all on the first or last day of a task.

A "Start day" allocation mode may be required for consumable resources that must be available in total on the day work starts - perhaps for reasons of economy in transport or unloading.

An "End day" allocation mode is often appropriate for materials like concrete. An activity covering the forming, fixing of reinforcement and placing of 500 m3 of concrete could take five days but the concrete may all be poured on the last day. If we were attempting to assess the peak need for transit mixers or concrete finishers it would be completely wrong to spread the concrete demand over the five days as an average of 100 m3 per day!

PROPLAN resources - as scheduling elements - also tend to be defined at a higher level than PROBID resources - which have to capture all the detailed costs that go into an estimate. In fact, PROPLAN resources may more closely match PROBID's Sets.

See the next topic for more info.

Back to Top

How do PROPLAN and PROBID work together?

If you are using PROBID - PROCON's Estimating & Tendering System - to produce your project estimates and tenders, you can export activities, operations, resources, sets and costs directly from the estimate to create a basic network plan.

PROPLAN can then refine this network and produce Bar Charts, Resource Loading histograms, Cash Flow histograms, etc., that support the tender submission and help in the estimate analysis of resource requirements and overheads.

General project information like the job name, password, department, job number, start date, duration and finish date is copied from the estimate to create an equivalent PROPLAN network. The project start and finish dates become the network data date and specified end dates respectively.

Some of the PROBID items, operations, resources, sets and costs are also copied to the network.

A PROPLAN activity is created for each operation assigned an Activity Code. The activity description, calendar, duration, start and finish date, costcode, measure unit and budget quantity are taken directly from the PROBID operation.

PROPLAN treats Start dates as "PUSH" (Earliest Start) dates, and Finish dates are "PLUG" (Latest Finish) dates. Any difference between the dates and the duration is float.

Any PROBID resource or set, used by an activity, is copied into the PROPLAN network as a resource. (Sets are treated as if they were a resource.)

Allocations of defined resources and sets are treated as assignments of consumable PROPLAN resources. These allocations are treated as fixed amounts equal to the calculated element quantity.

Any other operation costs (i.e., from subcontractors or undefined resources or sets), are assigned to the activity's direct budgeted fixed cost or budgeted unit cost - as appropriate. PROPLAN can then be used immediately to produce a simple Barchart or Resource Loading histogram or the network can be further developed by defining specific work calendars, logic links, milestone dates and hammocks.

PROBID also exports all estimate cost and revenue data in a form designed to assist the estimator in producing a quick cash flow analysis of both costs and revenue.

It is often not practical - and should not be necessary - to define every PROBID operation as a PROPLAN activity and assign it a code, calendar, start date, etc. (An estimate often contains many operations that have to be priced, but would not be included in a project schedule.)

However, for costing and revenue and cost cash flow projections it is essential that all costs, etc., are transferred to the PROPLAN network.

Each PROBID item is copied to a corresponding PROPLAN hammock. The hammock code, description, measure unit, budget quantity and bill unit rate are taken directly from the item. (If a number of PROBID items have the same code, the hammock codes are made unique by appending sequential lowercase alphabetic characters.)

The hammock's start and finish activity codes are taken from the activity codes in the item's operations. The start activity is taken from the operation with the earliest start date, and the finish activity from the operation with the latest finish. This ensures that the hammock spans all of the item's operations.

If some item's have no operations - or no operations with activity codes - the export facility will create two dummy "activities" to represent the job start and finish and uses these as pivots for the "unhung" hammocks.

The PROPLAN hammock's budget quantity is set to the PROBID item's actual quantity, and the bill unit rate to the item's submitted rate.

PROPLAN's REVENUE CASH FLOW report can then produce an immediate projection of periodic billing amounts and the profile and interest cost/value of the projected revenue stream.

This export facility also creates a set of artificial PROPLAN "resources" and allocates these to the PROPLAN hammocks. These resources are dummies for various cost and revenue combinations, so that the hammocks can capture the detailed cost breakdown from the corresponding PROBID item.

PROPLAN can then produce RESOURCE LOADING histograms for any of these dummy "resources". These resources are Consumable, are allocated as Fixed Amounts and are measured in thousands of currency units.

Each cost type (Labour, Materials, Subcontract, etc.) will typically have a different disbursement lag. This detailed breakdown by cost type provides the PROBID estimator with the option of fine tuning cash flow projections to produce more realistic figures for interest cost. The job cost and revenue detail is thus provided in several different forms. Before working with job totals of budgets or cash flow you must decide which form best suits your needs and disable the presentations that are not required. The hammock resource allocations can be removed by deleting all hammocks, deleting the artificial resources, or just zeroing their unit cost.

Back to Top

Is PERT COST a useful costing system?

Having broken a project down into tasks for purposes of time control, it seems only logical that we should use that same breakdown for cost control.

The resource assessment, required to estimate durations, could be used to generate a budget for each task - and hence a budget or "estimate of cost" for the complete project.

Progress assessment for time reporting could be tied in with valuation assessment for cost reporting - avoiding duplication of effort and providing some assurance that the two processes are harmonized.

This approach to costing - called PERT COST because of its early association with PERT networks on major defence development projects - is the basis for all the costing systems "built in" to Project Scheduling software, including PROPLAN.

Despite this intuitive appeal, attempts to apply PERT COST concepts in the construction industry have been particularly unsuccessful. Some of the reasons for this are:-

A task breakdown is determined by precedence logic - a cost breakdown should be determined by the logic of work similarity. When this is done, cost centers usually cut right across the task breakdown.
The granularity of the breakdown rarely matches. Tasks often include work of many different types - cost centers usually include work from many areas and stages in the project. Things that are important for purposes of time control (approvals, etc.) are not as important for cost control and vice versa.
Reporting frequency, completeness, and required accuracy, differ. Valuation and cost reporting is usually undertaken at the end of fixed periods (daily, weekly, or monthly) while time progress reporting should be an ongoing process with the timing of formal updates determined by project status.
The resource and cost assessment required for a budget - or cost estimate - is vastly more detailed than that required to develop a time plan. When task duration is determined by resource availability/usage (and often the reverse is the case) it is usually dependent upon only one or two "key" resources. In this case it is only necessary to consider these resources in time planning. Estimating and Costing must deal with all resources and costs.

PROPLAN has special capabilities that address some of these problems:-

A single costcode can cover any number of tasks - so costs can be allocated to broad aggregates, while valuation is still performed at task level.
Hammocks - as well as activities - can be directly costed. This provides more flexibility in handling overheads, indirects, and "global" costs, by avoiding the need to artificially spread common costs over sets of activities.
Resource based or directly allocated costing - or both - can be used.
Directly set budgets can combine a fixed and quantity related component.
Valuation progress is not rigidly tied to time progress.

Nevertheless, PERT COST cannot be recommended as a viable substitute for properly designed construction job costing systems.

Back to Top

 
PROCON CONSTRUCTION SYSTEMS
3/5-7 Victoria Parade, MANLY NSW 2095, AUSTRALIA
Tel: +61.2.9977.6863
Email: Information      Sales      Support

PROBID, PROBILL, PROCOST, PROPLAN and PROCALC are all PROCON trademarks.
Last modified: 17 July 2012
Top of Page                                                                 Home Page