This component is not part of the systematic map per se. We originally preregistered a plan to conduct an updated meta-analysis of the illusory truth effect (https://osf.io/j6fmr/). As part of the pilot testing in that plan, intended as a first stage to help develop an appropriate coding scheme, we each independently coded a random selection of papers from those included in the Dechêne et al. (2010) meta-analysis. It quickly became apparent that these papers did not report sufficient information to estimate the observed effect size for the illusory truth effect. Out of the 12 studies we coded, zero reported SDs (see yellow highlights in the attached file). Dechêne et al. (2010) encountered the same issues of underreporting. Out of the 51 studies included in that meta-analysis: - 21 provided standard deviations for the reported means; - 7 reported a range of standard deviations. The authors computed the pooled standard deviations from the range; - 23 did not report standard deviations. The authors imputed the pooled standard deviation from an overall estimate that was obtained from those studies in which standard deviations were reported or could be extracted (Dechêne et al., 2010, p.243). We concluded that a valid meta-analysis on the entirety of the illusory truth effect literature was not possible. As such, the pilot coding found here **was a work in progress**. We are reporting it for completeness, but the contents of the pilot will not be used for the systematic map.