“…Third, leading scientists in the field of neuropsychology of OCD were contacted and asked for unpublished studies and additional data. Of 17 research groups, 14 responded, and three of them (Exner, Martin, & Rief, 2009;Jang et al, 2010;Tumkaya et al, 2013) provided unpublished data that was included in the meta-analysis. The studies had to meet the following inclusion criteria: (1) Adult patients (18 years or older) diagnosed with OCD according to the Diagnostic and Statistical Manual of Mental Disorders, third edition (DSM-III), fourth edition (DSM-IV), or fifth edition (DSM-5), or the International Classification of Diseases, ninth revision (ICD-9), or tenth revision (ICD-10); (2) comparison of washing and checking symptom dimensions; (3) at least one dependent variable consisted of neuropsychological test performance; (4) studies reported statistics (means, standard deviations and sample size or t, F, r and exact p) that were convertible to effect sizes, (5) published in English, French, or German.…”