Estimators and Work Breakdown Structures – How Estimating Software Help

As the construction delivery process evolved over the years, estimators worked harder to provide different styles of information to different end users. Given the tools of manual, spreadsheet, and spreadsheet-based estimating, it was all an estimator could do to produce an old 16-division style estimate, with perhaps a few subtotals added within self-performed trades. Such formats sufficed for the traditional bidding general contractor. But to a company that provides construction management or design-build services, or that functions as one part of a project delivery team, reliable cost information must be associated with building components that can span across traditional breakdowns. Different design alternatives, sometimes based on green building standards, must also be evaluated. Without tools designed to deal with this problem, estimators waste time and risk errors by constantly juggling the “real” estimate – almost always in 16-division style – to produce the “show” estimate, which after changes and revisions would have to be shoe-horned back into the “real” estimate, and the cycle would repeat indefinitely until the right combination of cost-time-quality could be forecast.

Fortunately, modern data-based estimating software makes it easy for estimators to encode their work with multiple work breakdown structures. The end product–the estimate–is cross-coded to as many different views of the cost data as are needed. The estimate can be changed or modified in any view, then re-sorted and re-presented as needed. The key to this powerful capability is that estimate data is stored at the lowest level, coded to all necessary views, and then summarized, viewed, and reported as needed. Editing of prices can be done at whatever level is appropriate to the need; for example a change to a composite unit price for a flooring system can be drilled down into its component items. When these same items are re-sorted into a trade-style breakdown, they will retain the change made at the composite level, even though they now may be grouped in an entirely different manner.

To make it easy for the estimator to correctly code the estimate, there are three principal ways of assigning codes:

Default-assigned – Items pulled from the pricing database are already tagged with WBS (work breakdown structure) codes. As an example, a database item for excavation of concrete footings may carry an additional tag associating it with wall foundations, and no further effort is needed from the estimator to obtain a trade-oriented as well as a function-oriented breakdown.

Estimator-assigned – As takeoff and item entry proceed, WBS codes are selected from a pre-populated pulldown of valid codes. As an example of using this technique, when an estimator takes off a concrete wall, it can be tagged as a foundation wall, shear wall, exterior wall, interior wall, or whatever function it performs. The resulting estimate line items will carry this tag forward as well as their trade-oriented codes, allowing the estimate to be viewed by trade or by function. At the same time as this choice is made, the estimator can tag the items to a given area of the project, floor, or construction phase, providing a third view of the estimate.

Automated, Intelligent Assignment  - As takeoff is entered, the estimating software automatically chooses the correct coding based upon normal takeoff data entered by the estimator, with no additional effort required of the estimator. An example comes to mind regarding interior drywall partitions. A company may want to classify partitions by a combination of height ranges, core construction, and layering. The default-assigned method is impossible, because the same materials could fall under any of the possible partition classifications. The estimator-assigned method would require time-consuming navigation through a long list of all the possible combinations of height range, core construction, and layering. But with intelligent assignment, the estimating software can study the dimensions and specs as entered, and select which of the codes to use. Going further, a user could omit the long list, and let the estimating software actually build a code that encompasses all of these variables, assign it to all the work items (studs, board, tape, base, etc.), generate its description (16ga 3-5/8 Studs, 8-10’High,2-Layers FC Drywall Each Side) and even generate a high-level quantifier (in this case, probably linear foot of partition) that allows the estimator to see and adjust a composite unit cost for the partition.

Most real-world situations are best served by a combination of these three techniques. In integration with digital takeoff programs and with BIM, it is important that the estimating software be able to pull in the coding work already done without re-entry. Typically, in addition to dimensional data, these programs already carry identification as to areas, layers, type of component, construction phase, and a number of other codes. With no more effort on the part of the estimator, these codes can add extra richness and capacity to the analysis of the estimate.

In an effort to cope with industry changes, the art and science of estimating has changed greatly in the last 10 years. In order to meet its customers’ needs, specialized estimating software is continuously revised and updated. The ability to easily handle multiple views of an estimate is a distinguishing characteristic of high-quality estimating software.

By Kevitt Adler, president, MC2