Methodological Issues on the Importance of Instrument Validation in Cross-Sectional Health Research

Dear editor, Recently, we read with great interest the article authored by Jadidi et al. [1] that was entitled“Is emergency medical services (EMS) in Islamic Republic of Iran practical and efficient in facingEbola?” and published in Bull Emerg Trauma in 2019, in 7th volume and 3rd issue. First of all, wewould like to extend our gratitude to the authors of this article. Although the mentioned study wasappropriate and valuable, there was a fundamental flaw in the method, which has led to an ambiguous interpretation of the findings. Therefore, the purpose of this letter is to raise concerns about the data collection instrument and emphasize the importance of reporting its validity and reliability in crosssectional studies.