Question

A randomized clinical trial ends with a non-significant finding: treatment and control are not significantly different. However, the investigators notice that there is a significant treatment effect among participants who were smokers (i.e., subjects who, at baseline, reported smoking at least 5 cigarettes / day). Give one argument against pursuing this finding by conducting a new trial limited to people who smoke at least 5 cigarettes / day. Give one argument in favor of pursuing it.

Answer 1

Argument in favor:

Although the study reported that the statistical result did not show signficant difference between the two groups, but since the effect within the treatment group was significant, this means pursuing a trial using only smokers could lead to a potential new discovery that could help them lower their smoking effects atleast to some extent. Something is better than nothing is an argument in favor of this new trial.

Argument against:

Since the difference between the two groups was not significantly different, it is not worthwile to conduct a new study using the same treatment because if the treatment was not able to produce a significant result as compared to the control group, then it is better to devise a new treatment protocol rather than conducting a new trial involving smokers only.