Is the following accurate?
The ENR CCI is a general purpose index used to chart the costs of basic construction materials. It is a set of weighted aggregate cost indexes within which the quantities are kept constant. Costs are based upon the total annual production of the materials and the associated aggregate worker rate. The ENR CCI is NOT based upon the quantities of materials used in construction, nor does it incorporate factors for productivity, managerial efficiency, competitive conditions, or contractor overhead and profit. Weights are then applied to these value by industry “experts” on the relative importance of the components to construction. The ENR BCI incorporates the same methodology, however, substitutes skilled labor for common labor, with skilled labor consisting of three trades…bricklaying, carpentry, and ironworkers, vs. non-farm worker values used in the ENR CCI.
RSMeans products a historical cost index (HCI), a weighted aggregate cost index. Unlike the ENR, RSMeans uses actual average usage of quantities in “average” current building practice. The average building is an average of five building types (warehouse, school, high rise apartment building, medical office building, low rise housing) of a certain size and cost. The quantities and costs represent approximately 80 construction materials, 24 trades, and 9 types of construction equipment. Materials and quantities are “taken-off” in the same manner commonly used by contractors and subcontractors. The Historical Index page can be used in conjunction with RSMeans City Cost to move any cost from one city and time to another city and time. The RSMeans CCI is calculated in the same manner as the HCI and is available for over 900 zip codes. Custom CCI’s can be created to reflect specific locations.
Technically the RSMeans material prices are national average. Several prices for each material are obtained and mathematically averaged. Some data sets are based on a 30-city average for union labor rates, while others use open shop labor rates and still others use residential labor rates. To correct prices for your location, for each CSI Division multiply the bare material cost by the MAT Index for that city. Likewise, multiply the bare labor cost by the INST index for the city. If the desired activity has an entry in the equipment column, multiply this cost by the equipment rental index. It is more accurate to use the indexes on the material and labor costs separately rather than using the Total index on the Total Including Overhead and Profit values. This is especially true for those lines where there is a large difference between the material and labor costs.
The RSMeans CCI is broken down by trade (Construction Specification Institute /CSI) division number. At the bottom of each city is the weighted average. This average is weighted by giving more value to the more expensive components of construction and less influence to those items that are usually the least expensive. The Location Factors are just these weighted averages. If you are concerned with the total building (all trades), then the weighted average is fine. However, if you are just concerned with a particular trade, use the City Cost Index value for that trade.
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