The methodological principles of the ICHTrev-TS are presented in detail in the ICHTrev-TS methodological note.

The revised Hourly Labour Cost Index - All employees (ICHTrev-TS), like the ICHT-TS it replaced in 2009, is non-revisable. It is a chain-linked Laspeyres index, with a base of 100 in December 2008. It is computed quarterly, smoothed using a 4-order moving average (i.e. over the last four quarters) to ensure less volatility of the index, and then made monthly using linear interpolation.

The ICHTrev-TS is determined by relating the sum of the payroll and social charges, after allowing for exemptions, to the hourly volume of labour.

In December 2023, Insee has reduced the publication deadlines of the revised index of hourly Labour Cost (ICHTrev-TS). As of this date, this index is now published approximatively 75 days after the end of the considered quarter (compared with 100 days currently).

Nota Bene: The ICHT-TS, published from 1996 to 2008, was only based on the basic salary. The revised ICHT takes account all elements of the wage (premium, bonuses, overtime pay) in addition to the increase in the qualification structure.