Frequency is measured as reported, undeveloped lost-time claims at a first report per million dollars of earned premium. The measure is adjusted to a common wage level and on-leveled to NCCI-approved pure loss cost level by state.
The data is based on NCCI’s Statistical Plan data for private carriers and state funds in all states where NCCI provides ratemaking services.* Large Deductible policies are included; underground coal mine policies, F-classification experience, and COVID-19 claims are not included.
The data is summarized at an industry level by leveraging the reported North American Industry Classification System (NAICS) codes in NCCI’s Policy Data.
We utilize NAICS codes instead of NCCI’s Industry Groups, as NAICS codes more closely match the Economic Insights shared and here’s why. The NAICS codes are used to categorize a business or an individual policy, while NCCI’s Industry Groups are a mapping of workers compensation classification codes to five industry groups for our class ratemaking procedure.
For example, a policy with the construction NAICS code reported in the Policy Data would be assigned to the NAICS construction code for this analysis. However, if we were to apply NCCI’s Industry Group structure, only the construction classes on the policy would map to the Contracting NCCI Industry Group, and the data for any clerical classes (e.g., Code 8810 payroll and losses on the same policy with construction classes) would map to the Office and Clerical NCCI Industry Group.
*AK, AL, AR, AZ, CO, CT, DC, FL, GA, HI, IA, ID, IL, IN, KS, KY, LA, MD, ME, MO, MS, MT, NC, NE, NH, NM, NV, OK, OR, RI, SC, SD, TN, TX, UT, VA, VT, WV
Data for the Series Overview, Construction, Manufacturing, Retail Trade, Transportation and Warehousing, and Wholesale Trade industries reflects Unit Data submissions received as of January 2024. Data for the Leisure and Hospitality, Office, Education and Health Care industries is received as of April 2025. NCCI’s Industry Trend Report features data for all industries received as of April 2025.