In AskiaSurf, a wave is a discrete section of a piece of ongoing research (or campaign), usually being conducted over a specific time period, such as a month. Two or more waves make up a campaign and each wave typically uses a different version of the questionnaire (questions are modified, added and removed as the research requirements dictate). For example, a continuous study (or campaign) might comprise twelve waves per year, each conducted over the course of a month.
AskiaSurf reconciles the data from the campaign's waves, allowing you to perform analyses of the data over time (e.g. to track the performance of a product over a year, or to compare sales in the same month in successive years).
The files or databases that contains the data for a wave are known as volumes.