12.1. Introduction. The present chapter provides additional clarification on the statistical concept of time of recording, as defined in IMTS 2010, chap. I, on scope and time of recording, and describes good practices in the approximation of time of recording in the use of both customs records (see chapter II of the present Manual) and non-customs data sources (see chaps. III and IV). Section A provides an overview of the basic concept and data sources for determining the time of recording, while subsequent sections provide additional details regarding the determination of time of recording under different circumstances and in different cases.