In three studies the findings were

In three studies the findings were inconclusive, for
three reasons.w2 w17 w21 Firstly, when there were multiple
outcomes for smoking behaviour, some were positively
influenced by the intervention (self reported abstinence
in previous 24 hours, percentage smoking
within fiveminutes of waking), whereas others were not
(self reported abstinence in previous month, attempts
at quitting, and numbers of cigarettes cut down).w2