Yesterday, Today, Tomorrow

This trio of radio buttons occurs in the dialog for every question. It controls which day we obtain in answer to the question. Using the default value, today, we get the actual day when the answer to the question was true. Using yesterday, we get the day when the answer to the question was true yesterday, i.e., the day after the day when the answer to the question was true. Similarly, tomorrow gives the day when the answer to the question is true tomorrow, i.e., the day before the day when the answer to the question was true.

The use of yesterday, today and tomorrow is intended to be colloquial rather than precise; yesterday actually means "the day immediately before this one in the database" and tomorrow means "the day immediately after this one in the database."