Abstract
Disruptive secondary school students were given letters to take home at the end of lessons which had to be signed by their parents and returned to school the next day. Using a time‐series plus control group design, the relative effects of a teacher sending home positive, negative or a combination of the two types of letter home were compared. The issue of letters was contingent on students’ on‐task behaviour in class. In two experimental classes, although all three types of letters had significant effects, the negative letter was the most effective in increasing on‐task behaviour, followed by the combined use of positive or negative letters, and the positive letter condition. The results also showed positive ‘spill‐over’ effects on the on‐task behaviour of disruptive classroom peers who did not receive the letters home procedure. Possible explanations for the results are discussed. It is concluded that the letters home procedure was not only effective but required minimal commitment of teacher time and parent resources.