Manuscript ID: ICD-23-0031
Comments to the Author

This registered report proposes to investigate the psychometric properties of the Strengths and Difficulties Questionnaire (SDQ), a widely used questionnaire for screening for indicators of psychopathology, in a sample of 310 preschoolers in Turkey. In particular, the hypothesis is that neither the 3- or 5-facor solutions, usually supported by data collected in WEIRD (Western, educated, industrialized, rich and democratic) Countries, will fit these data, collected in a non-WEIRD Country. This result would have implication for the use of the SDQ, that would need to be more cautious. Although the report itself includes some strengths, some weaknesses of this proposal outweigh the potential value of the findings. The weaknesses are described below, separately for each manuscript’s section.

Abstract
“Turkey does not possess all of the characteristics of a non-WEIRD country”. I think this sentence includes a mistake; it should be “WEIRD” not “non-WEIRD”.
Also, the abstract should mention which version of the questionnaire (parents, teachers or both?) has been administered.

Introduction
- First paragraph: the total difficulties composite score (emotional symptoms + conduct problems + hyperactivity + peer relationship problems) should also be mentioned when describing the SDQ’s subscales.
- Section “Use of the SDQ in Non-WEIRD Countries”, first paragraph: it is not clear why the paragraph begins with the reliabilities and correlation scores of the Lai et al.’s study. First of reporting these (and other) results, an introducing sentence should be provided. Then, a comment to the results of the studies reported should be provided: for example, the data on the sample from Hong Kong reported are related to reliabilities and correlations, not directly factorial structure. What these results say something useful for the study’s topic, and what they suggest? This should be made explicit.
- P. 3 lines 42-47: Gaete et al. found a result different from some studies presented before and after within the same paragraph (confirmation of the 5-factor structure). To make easier to the reader following all the studies presented, it would be useful to put all the studies confirming/not confirming the original factorial structure together. Please do the same on the following section about studies on samples from Turkey.
-P. 5 lines 36-38: “sometimes is unclear and problematic”. Please explain what you intend as “unclear and problematic”.
-P. 5 lines 37-47: “The factor structure is important if researchers want to examine the subscales
separately. For instance, if one wants to identify peer problems or hyperactivity as a child’s
issue, then it is important that there is a clear factor structure that identifies those subscales as
distinct. Otherwise, only the total difficulties scores should be used when evaluating children
rather than subscale scores (Mieloo et al., 2014).” This part should be included before for presented the rationale of the study. Indeed, it should be clarified before describing the results of past studies, why it is important to investigate this topic. Also, why should we find a different factorial structure in non-WEIRD countries? This hypothesis is based only on past empirical data and on general “differences” between WEIRD and non-WEIRD countries, or is there a theory or at least another motivation guiding this hypothesis?

• Globally, the introduction lacks information on the age of children for which the SDQ was filled in in the presented studies. This variable is important and could potentially affect the factorial structure emerged from the data, so this information is needed, and the role of age should be discussed.
• Also, information on the version of the questionnaire administered (teacher, parent of self) is not always provided and it is an important information when interpreting the results of the studies presented.
• “Summary and present study” section. The two studies recalled report results on samples of immigrant and refugees, which beyond being from non-WEIRD countries, have many other peculiarities related to risk factors that make them a different sample compared to non-WEIRD countries general population. The Au also describes that in the following sentences. For these reasons, these should not be the studies mentioned for motivating the proposed data collection.
• “Participants” section. Is the sample representative of the Turkish population?
• “Materials” section. This section seems incomplete, the SDQ should be described, included scale of response, the source of the Turkish version of the questionnaire provided, or the description of the translation process, if it was made by the Au, described.
• The sections describing which data analysis is expected to be performed and the expected results are missing.