The main collection instrument is the Sexual Diary Form. This consists of a face sheet (containing relevant demographic and back-ground information), a partner list which is constructed as the diary is filled in, instructions for completing the diary and four one-week diary forms.

After completion of the natural language diary, the contents are encoded using the Sigma Diary Code into a database of which the record is the sexual session.

Although many diary coders will have committed the code to memory the weaker coder will need easy reference to the crucial components of sexual activity and these are provided on the Diary Encoding Card.