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S OURCES OF E STIMATION D ATA

S OURCES OF E STIMATION D ATA. 1. Company  s Own Cost Data From Previous Projects. Advantages It reflects quality and productivity of its own equipment and crews. It reflects company’s management system and construction methods. Limitations

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S OURCES OF E STIMATION D ATA

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  1. SOURCES OF ESTIMATION DATA

  2. 1. Companys Own Cost Data From Previous Projects • Advantages • It reflects quality and productivity of its own equipment and crews. • It reflects company’s management system and construction methods. • Limitations • Accurate field information should be collected and updated.

  3. Company's Historical Data Div. Work Desc. Unit Low Avg. High 2 Site work sf 0.30 0.35 0.39 2 Excavation cy 3.56 4.57 4.93 3 Formwork sfca 2.56 2.71 3.11 3 Reinforcement lb 0.35 0.38 0.42 4 Masonry (...) sf 5.82 6.21 7.34

  4. SOURCE OF COST DATA (Cont.) 2. Commercial cost books • published and updated periodically • contain specifications, labor rates, labor productivity, prices, photos, calculations, etc. The most common references are: • Means Building Construction Cost Data , R.S. Means Company • Dodge Manual, McGraw-Hill Cost Information Systems • Walker Building Estimator’s Reference Book, Frank R. Walker Company

  5. Limitations of Commercial Cost Books • They represent composite data (average of man projects) • They fail to recognize technological changes • There is a reporting time lag.

  6. SOURCE OF COST DATA (Cont.) 3. Published Data These guides are valuable to estimator who do not have access to actual job records. Vendor's Data information published by the manufacturer or distributor which usually gives the unique features and specifications relating to the product e.g. Sweet's catalog Periodicals gives various construction cost indices for all cites all over North America. e.g. Engineering News Records (ENR)

  7. 4. Prototype Modeling • Build a model for unique work where no published literature are available, • examples: spread concrete on an airfield parking ramp or mock up for building facade 5. Professional Associations • American Association of Cost Engineering AACE • National Estimating Society *Seminars, training organizations, publications

  8. 6. Previous Bid Tabulations • Available from previous bid openings (public works) • Generally, limited to the lowest three bidders

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