Although ENR’s indexes measure the costs of non-residential buildings, the housing market has had a major impact on index movement. The ENR 20-city average yearly price for steel rose 37% by the end of 2021, while the overall Materials Cost Index experienced an increase of 31%. Both skilled and common labor saw a modest gain. The ENR Building Cost Index increased 13.1% for the year, while the Construction Cost Index rose 7.4% over the same period.

ENR began reporting changes in materials prices and wages systematically in 1909, but it did not establish the CCI until 1921. It was designed as a general-purpose tool to chart basic cost trends and today remains a weighted aggregate index of the prices of a constant quantity of structural steel, portland cement, lumber and common labor. This package of goods was valued at $100, using 1913 prices.

The original use of common labor in the CCI was intended to reflect wage-rate activity for all construction workers. In the 1930s, however, wage and fringe benefit rates climbed much faster in percentage terms for common laborers than for workers in the skilled trades. In response to this trend, ENR in 1938 introduced its Building Cost Index (BCI) to weigh the impact of skilled-labor wage changes on overall costs.

BCI劳动力组件是木匠，瓦工和熨斗人员的平均工会工资率，再加上附带福利。材料组件与CCI相同。BCI还代表了这些建筑项目的假设包，1913年价值100美元。

这两个索引旨在指出美国建筑成本的基本潜在趋势，因此，组件基于对当地条件影响较小的建筑材料。新利18备用官网登录新利18备用Enr选择钢，水泥和木材，因为它们与美国经济有稳定的关系，并在建筑中起主要作用。

材料Choices

实际上，ENR选择了这些材料，因为所有三个材料新利18备用都可以使用可靠的价格报价，从而确保可以及时计算两个索引。尽管基于有限数量的组件，任何指数中可能存在一些弱点，但ENR认为，大量要素会增加验证价格和发布指数之间的时间滞后。新利18备用同样，与包括许多人在内的索引相比，组件较少的索引对价格变化更敏感。

On the downside, however, the use of only a few cost components can cause indexes for individual cities to be more vulnerable to source changes. These aberrations tend to average out for the 20-city indexes, which ENR recommends for general use.

由于索引以实际价格计算，因此指数内给定组件的比例将随其相对升级率而变化。

In the late 1970s, labor’s share of the index dropped because materials prices were in the grip of hyperinflation. In 1979, for example, lumber prices increased 16%, cement prices rose 13% and steel prices jumped 11%, but labor went up just 8%. These developments resulted in materials gaining a larger percentage of the index.

In the original CCI, the components were weighted at 38% for labor, 38% for steel, 17% for lumber and 7% for portland cement. The shifting tide of inflation changed the weight of the CCI components, making labor 81%, steel 13%, lumber 5% and cement 1%. This shift was less dramatic for the BCI, which is now 66% for labor, 23% for steel, 9% for lumber and 2% for cement.

两项指数均未根据生产率，承包商的开销或利润进行调整。但是，这些索引可以解决这些因素。通常，当生产率较低时，售价将相对较高，高于ENR指数。新利18备用通常，当竞争激烈时，完成建筑的售价将低于Enr的指数。新利18备用