- The main constraint is the document being analysed, the contents of which are determined by the purpose for which it created. It is important to remember that where something is not mentioned that does not mean that it does not exist or did not happen, but that it may not have been important to mention in this context.
- The evaluator has no control over the information available, and therefore cannot decide in advance the questions to which answers will be provided.
- The information can be inconsistent. Many different observers may have created the documents they observe and record different things, and certain information may be present in some and not others.
- The document can be quite distant from what actually happened, e.g. minutes of meetings, which will affect the validity of the data extracted.
- Content analysis of documents can be laborious.