National Highway Construction Cost Index Federal Highway Administration October, 2010 Ralph Erickson National Highway Construction Cost Index (NHCCI) • Replaces the FHWA Bid-Price Index • Uses Fisher Index to produce a quarterly index at the National level • Bid-Tabs data provided by Oman Systems, Inc. • Possible extensions – State level indexes – Component indexes Fisher Ideal Index • “Ideal” refers to the Fisher Index addressing changing ratios of inputs – Captures the effects of changes in the relative importance of different cost items in highway construction over time – Minimize substitution biases Index Data Requirements • Product requirements for isolating cost changes – Specific – Consistent over time • Continuity of time series for individual products (pay-items) • Sufficiently representative (and large) set of observations for statistical confidence Oman Systems, Inc. (OSI) Data • Captures State web-posted bids awarded on highway construction contracts • Partial data back to 1993 • Covers all contiguous States since 2007 • Composed of State-defined pay-items What State Bid-Items Measure • Cost of – Material – Installation (capital and labor) – Overhead – Profit • Not a measure of pure price changes – Such as the BLS Producer Price Index – PPI (for H&S) now discontinued OSI Data • • With judicious editing, OSI data can meet the above data requirements for indexes: Remove pay-item records: – Non-standard – Unit of measure (lump sum) issues – Suspect categories Non-standard • Same pay item number but have different pay item descriptions (or units of measure) between projects • Cannot be included due to the differing types of work from project to project Unit of measure issues • There are some pay items where the unit of measure makes it difficult to track price changes – Example: • Landscaping • Lump sum =1 • The prices bid on these items are not related to price trends Suspect categories • Categories of work such as start-up costs, incentives, etc. – Mobilization – Alternates/Bonuses/Time Further Data Edits • Eliminate records where pay-items: – • Lack eight quarters of consistent data Eliminate records where pay-items fail established variance tests – Rationale is to reduce data entry errors Edit Example • Eliminate records for pay-items : – Maximum observed price is more than 16 times the minimum price – Coefficient of variation is greater the 42 when evaluating the log of change in price times 100 – The “16” and “42” above vary by run Effect of the Edits • Overall effect of the edits (although large in number) still leaves a useful dataset for constructing the NHCCI • Remaining value is representative of all bid tabs expenditures with almost 40% of the original observations still available • The distribution of the expenditure categories which determine the weights in the NHCCI are largely unaffected by the edits Summary • • • • • The new FHWA cost index Data characteristics OSI data Edits to the OSI data Results Jun-10 Mar-10 Dec-09 Sep-09 Jun-09 Mar-09 Dec-08 Sep-08 Jun-08 Mar-08 Dec-07 Sep-07 Jun-07 Mar-07 Dec-06 Sep-06 Jun-06 Mar-06 Dec-05 Sep-05 Jun-05 Mar-05 Dec-04 Sep-04 Jun-04 Mar-04 Dec-03 Sep-03 Jun-03 Mar-03 2003 = 1.00 NHCCI Results 1.5 1.4 1.3 1.2 1.1 1 0.9 0.8 0.7 0.6 Resources • Ralph Erickson – 202-366-9235 – ralph.erickson@dot.gov http://www.fhwa.dot.gov/ohim/nhcci/