The political scientist uses oral testimony to record events which happened sometime not too long ago. He retrieves documents about events, usually from eyewitnesses but sometimes from descendants of eyewitnesses. Whenever a witness testifies to events and his testimony is recorded, the following sequence or chain between the events and the record of them has taken place:

The relation between the events and the events as described in the document has therefore undergone the following “distortions”: events--part of the events are perceived--part of the perception is stored in the memory of a man and colored by his personality--part of what is in the memory of the man is released and the release is colored by the interview. There is quite definitely a loss of information between the event and the record of it. There is also, and this is less obvious, quite an accretion to the record of the event by the reflections and the personality of the witness. The aim of the person who uses the record is to know what are the accretions and the distortions so that he would know what actually happened insofar as it is recorded. Critical analysis is the tool used to discover this. It can be made much easier if certain items of information besides the testimony and about it are available. It is therefore of great value to collect this ancillary documentation together with the oral testimony itself.