If so , how big was the effect ? What are the stats ?
If so , how big was the effect ? What are the stats ?
Regarding the self-measurements influencing the results: the wisdom in the participants' reasoning (the dependent variable in the focal study) was evaluated by two independent hypothesis-blind raters. This seems like a pretty solid evaluation of the participants which should be immune to anything but the manipulation the researchers employed (the diary conditions). I am not sure what self-measurement you are concerned about.
The main results are an interaction between Time (pre/post) and Diary condition (3rd person/1st person), t = 2.65, p = .008. They followed this up with a contrast showing that the 3rd person diary condition resulted in more wise reasoning post-intervention (as compared to pre-intervention), B = 0.130, SE = 0.028, t = 4.61, p < 0.0001. And importantly, this same improvement was not seen in the 1st person diary control group: B = 0.022, SE = 0.030, t = 0.74, p = 0.458.
They didn't provide degrees of freedom for their t-tests, but given their sample size (N=298) they're essentially z-tests anyway.