Project Management: Cost Estimates without Production Drawings

Suppose that an estimate is to be prepared for the manufacture of a box filled with instrumentation, but that no production drawings have been prepared. Only one box is to be made, since it will be required for a special project. The only description on which the estimates can be based is an artist's sketch showing the exterior of the box, and an engineer's written design specification which includes no detail at all of dimensions, materials or the contents of the box, other than to outline the functional performance of the completed product.

Standard estimating tables are not likely to be of any help at all in this kind of situation. Build-up of standards depends upon the establishment of production continuity, which demands in turn that a certain minimum volume of production must take place. Such standards cannot be applied to 'one-off' production, where the unknown variables take over to dominate the picture. In any case, there are no drawings from which to break the work down into operations, and so the standards – even if they were valid – could not be applied.

A stage in the project planning process has now been reached where many professional estimators, production engineers and work study devotees find themselves foundering well out of their normal depth. Their trusted books of standard times, with which they have worked for many years, and much of their professional training will become virtually useless when they are faced with the problem of estimating for work where no drawings exist. They have learned to regard drawings as their customary means of expression and communication. Without such aids they are rendered helpless. They feel deprived and are quite unwilling to commit themselves to giving forecasts which may require justification later.

There is no simple solution to all of these problems, but it is possible to outline a new line of approach which is more likely to yield results. Fortunately, the lack of drawings and the necessity for making estimates in a short space of time are two conditions which demand a similar handling technique. Project estimating, as has already been seen, is carried out on a much broader scale that run-of-the-mill production work. Larger work packages must be visualized. With the broader view the level of seniority of the estimators rises until the production manager himself could become involved.

With the example of a metal box filled with instrumentation, the estimating method might proceed along the following lines. First a description of the proposed box would be needed, with some idea of its contents. The engineers must provide this information since they are the only people at this stage who can possibly have any real idea what the final, detailed article will be like.

Once a description of the new box has been set down it is usually possible to find a previous piece of work which bears some resemblance to the new job. Once again the engineers are the only people who can be asked to make such comparisons at this stage. It might be said that no direct parallel exists but that one previous job was carried out which was somewhat simpler than the present object of concern. 'How much simpler?' is the question which must now be asked. The engineer may say that about 10% more components will be needed this time, giving a basis on which to approach the production department for an estimate.

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John Reynolds has been a practicing project manager for nearly 20 years and is the editor of an informational website rating project management software products. For more information on project management and project management software, visit Project Management Software Web.

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