Module 3 · Preliminary disparity index

Utilization measured against availability

The disparity index divides a group's share of spending by its share of the available firm base. A value of 1.0 is parity. Below 0.80, the convention used across disparity studies, flags substantial underutilization. These are preliminary, public-data-derived values.

Preliminary, public-data-derived. Not a Croson-defensible finding.

These indices combine public availability (Census ABS) with public utilization (the County's FY23 SWaM report). They are directional and subject to revision with primary contract and bid data. They do not establish discrimination or support a remedy on their own.

This is the surface read, by design

The index on this page divides a group's share of dollars by its share of firms. It is the basic measure any disparity study can produce, and it shows where to look. It does not, on its own, explain why a gap exists, where in the procurement process it arises, or whether it survives once legitimate differences in firm capability are accounted for. That deeper, causal work is the heart of our approach.

See how we go beyond the ratio

Minority-owned index

0.24

util 9.0% ÷ avail 37.2%

Women-owned index

0.19

util 4.9% ÷ avail 25.4%

Threshold

0.80

below this flags underutilization

Preliminary disparity index by group

Countywide. Utilization ÷ availability, with the 0.80 threshold and parity marked.

Source: ABS 2022 (availability, CBSA 47900) and Fairfax County FY23 SWaM Report (utilization).

Disparity index by group and industry cluster

Each cell is the index for one group in one procurement cluster. Color runs from deep red (severe underutilization) to green (parity).

< 0.40 severe0.40–0.600.60–0.800.80–1.00≥ 1.00 parity

Group \ Industry cluster	Construction	Professional & Technical Services	Information Technology	Goods & Commodities	Other Services
Minority-owned	0.26	0.25	0.39	0.24	0.21
Women-owned	0.47	0.17	0.33	0.23	0.18

Source: Availability by cluster from ABS 2022 (CBSA 47900). Utilization held at the countywide group level from the FY23 SWaM report (see assumption below).

The one assumption in the matrix

Fairfax does not publish utilization by industry category, so the matrix holds utilization at the countywide group level and lets availability vary by cluster. Both inputs are real public figures. The assumption is that diverse-spend rates are uniform across clusters, which the full study removes by reconstructing utilization from transaction-level contract data. Where availability is highest, the implied gap is widest.

How to read a cell

A construction cell of 0.26 means minority-owned firms are used at about 26 cents on the dollar relative to their availability in that cluster, a reading of substantial underutilization. The full study attaches a statistical significance test and anecdotal corroboration to each cell.

How Fairfax compares to peer regional studies

Disparity index (utilization ÷ availability) across regional disparity studies. Every one falls below the 0.80 threshold.

< 0.40 severe0.40–0.600.60–0.800.80–1.00≥ 1.00 parity

Source: U.S. Census ABS Company Summary 2022 and Nonemployer Statistics by Demographics 2022 (NES-D), CBSA 47900; peer disparity studies (WMATA/Keen 2021, Commonwealth of Virginia/BBC 2020, WSSC Water/MGT 2022).

Reading the comparison honestly

Every regional disparity study finds substantial underutilization, with indices well below the 0.80 threshold. Fairfax's preliminary, public-data indices fall in the same range. The peer figures come from full primary-data studies; the Fairfax values are preliminary and will be refined by transaction-level data. WSSC Water (MGT, 2022) reported M/WBE utilization of 33.2 percent and adopted MBE-program revisions on its findings.

What a defensible index requires Index by sector in the explorer