There are basically two types of survey: descriptive and explanatory (Passmore et al.,
2002). Descriptive surveys capture factual data or opinions. Factual data can be gender,
age, number of searches per day, etc. while opinions can be the preferred search engine,
best organisation of search results, etc. Explanatory surveys attempt to capture cause
and effect links (e.g. whether highlighting the query terms in a search result improves or
worsens the search experience). Typically, surveys are both descriptive and explanatory.