A reference period is the time period for which statistical results are collected or calculated and to which the data refer. The time period may be a calendar year (reference year), a fiscal year, a semester, a quarter, a month and even a day (reference date).
The reference period should be distinguished from the publication time, the period or point in time when the statistical data are published. The publication time of statistical results is later than the reference period for which they were collected, due to the time it takes to treat and verify the data.
Example
Data on the labour market is published in April - this is the publication time. In April 2023 the data published refer to the labour market situation in 2022, the reference period.