The methodological principles of the labour cost indices are presentend in detail in the LCI methodological note.

The LCI, for the hourly cost index itself, is determined by relating the sum of the wage bill and social charges, after allowing for exemptions, to the hourly volume of labour.

It is a chain-linked Laspeyres index, with a base of 100 in 2020, which can be revised every quarter.

Its European harmonisation allows comparisons with the different Member States. As the European regulation stipulates, in addition to the LCI – hourly costs, INSEE calculates another index: the LCI – hourly wages.

Based on the same data sources and for the same business sectors, the LCI – hourly wages tracks changes in the average gross hourly wage. It is therefore an hourly labour cost index - excluding employers' social security contributions.