An information gap activity is an activity where learners are missing the information they need to complete a task and need to talk to each other to find it.
Learner A has a biography of a famous person with all the place names missing, whilst Learner B has the same text with all the dates missing. Together they can complete the text by asking each other questions.
In the classroom
Information gap activities are useful for various reasons. They provide an opportunity for extended speaking practice, they represent real communication, motivation can be high, and they require sub-skills such as clarifying meaning and re-phrasing. Typical types of information gap activities you might find include; describe and draw, spot the difference, jigsaw readings and listenings and split dictations.