The aim of this study was to examine the validity of data entered in participating subjects' TV, video, and video game viewing/usage diaries.

The participating subjects were eight families with third and fourth graders in the Tokyo Metropolitan Area. The amount of TV viewing (total and by TV channel), viewing of video-recorded TV programs, and playing of video games by third and fourth grade children were recorded in the viewing/usage diary and at the same time measured by a viewing state measurement device. The correlation coefficient between the data obtained from the diary and that from the measurement device was equal to or higher than the coefficient obtained in a preceding study, confirming the validity of the data entered in the viewing/usage diary.