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General Rules for Estimating Contract Work

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GENERAL RULES FOR ESTIMATING CONTRACT WORK An estimator should rigidly adhere to the fol lowing general rules: 1. Make all estimates in the fullest possible detail.

2. Get together and classify all the available data before commencing to figure.

3. Use a carefully prepared standard sched ule of items for the classification.

4. Go over the ground with great care—vis iting the site of the work, if possible—to guard against the omission of items not provided for in the standard schedule.

5. Put down all the unit-quantities first; then all the unit-prices; and finally, make the arithmetical computations in such manner that you will not know even approximately the final results until all the figures have been thoroughly gone over and tabulated.

6. Check over the final results by every available means, such as contract prices on simi lar work, which are unsatisfactory as prelimi nary data, but may be very useful as a check.

The reasons for these rules are as follows: 1. At first sight it would seem that it re quires more labor and time on the part of the estimator to make estimates in elaborate detail than to make them in general. This, however, is not the case according to experience, since a much larger part of the detailed estimate can be done mechanically than when many of the items are lumped, and because the more elaborate the detail, the more confidence a man has in his own figures, and the faster he is able to work.

General Rules for Estimating Contract Work

When an estimate is made in careful detail, gaps in the available information become apparent; and in this way it is easy for an estimator to know just what information he lacks, and where the dangerous parts of his estimate are likely to be. Then, again, an estimate made in detail is much more easily checked by the subordinate or by the estimator's superior officers; and, when filed for reference, such an estimate is a docu ment of great utility in future work. When the field costs are properly prepared, they can be used to check up the estimate for the work, in a way that is not possible if the estimate is not made in full detail.

2. It is a psychological fact—one based on the natural tendencies of the human mind—that if an estimate is made as the figures come in, it is impossible to obtain as good a grasp of the general problem as when the data are first col lated, and the estimate then prepared on the data. While the estimates should be made in full detail, this does not mean that they should be made for different items of the work inde pendently, since all parts of a piece of construc tion work are to a large extent dependent upon one another; and thus, if the estimated cost of one item is set down before the other items are known, their interdependence or mutual rela tions will not be appreciated and will not be allowed for in the estimate.

3. Rolling off a log is a difficult and elab orate feat compared with forgetting items in an estimate; and it has been found, from wide ex perience, that the best way to avoid omitting items is to start with a standard schedule. To

write a zero after an item that is not going to come into the estimate, takes practically no time; and the use of such a schedule in all cases is ex cellent insurance against blunders. A good plan is to have such schedules in stock, printed on sheets of coarse-ruled paper.

4. It is a sad fact that a great many esti mates are made without the estimator ever see ing the work. This is utterly wrong; and it should be an invariable rule that the estimator must go over the ground, and go over it thor oughly; else it will be impossible for him to use the essential quality of judgment. Moreover, there is nothing like a physical view of the field for enabling a man to grasp all the details of the work. For this purpose, plans are of great as sistance in the detailed analysis; but they are no substitute for a good look at the ground.

5. An estimate, to be accurate, should be ab solutely unbiased; and where a question of judg ment is involved, it is essential that the esti mator make his figures without regard to what they will amount to in the grand total.

6. After the grand total has been computed, it should be checked; and the checks may throw some light upon erroneous items, which can then be corrected. The estimator's judgment will be a great deal more accurate if he works the prob lem out in detail first, than if he tries—perhaps sub-consciously, or without fully realizing the fact—to work to a desired or hoped-for result.

The practice of taking somebody else's con tract price as a base for figuring, is very decep tive if you do not know what specifications he had, how he intended to do his work, what layout he anticipated, and what his financial arrange ments were. All of these items are of the utmost importance in figuring the economics, or the financial features, of any particular piece of work. Conditions vary in places short distances apart; rates of wages vary in different parts of the country; specifications, and the interpreta tions of identical specifications by different en gineers, vary greatly; the bid prices are fre quently too low or much too high; the bid prices may be purposely "unbalanced"—that is, made abnormally high on certain items, and abnormal ly low on others, but always so as to offset one another and "even up" in the grand total; a unit-price for a large job is usually too low for a small job, on account of the falling percent ages, or relatively lower rates, of overhead charges and superintendence on the larger jobs; a contractor well equipped with plant can usu ally bid lower than contractors not so equipped.