The Project Sigma Sexual Diaries were encoded using a precise sexual language capable of expressing all forms of sexual behaviour. This language is referred to as the "sexual diary code" . Using the sexual diary code data from each diary were entered originally into a database, "Cardbox^TM", (now also available in Access or Excel format) and subsequently analysed by a suite of MS Dos-based programs developed for the purpose known as the "Sexual Diary Analysis Program Suite".

Detailed documentation of this process and on using the suite is contained in the manual "SDA Program Suite Documentation" (1.4MB).

The Programme suite itself and sample analysis files are contained in  "SDA.zip" (422 kb).