Although a few researchers mention that involving interpreters can have an impact on the research process and research findings, little is published regarding methods of assessing the interpretation work's quality and impact. The impact of lay volunteer interpreters used in audiorecorded semistructured interviews on collecting data and the data quality and subsequent analysis is examined. A new systematic approach is presented comparing original interview transcripts (conducted with volunteer interpreters) with independent transcripts, reinterpretations by professional interpreters. Findings indicate that involving volunteer interpreters had an impact on the validity and reliability of a portion of the data, the subsequent analysis, and some practical research aspects. Researchers involving interpreters should pay careful attention to the interpreters' influence on the research, the data produced, and critically bring this to bear in their analysis and interpretation. The systematic comparative approach is a cost-effective tool that can be used successfully to examine the influence's effects.