1. A procedure or technique whose validity, ethics, or effectiveness is doubtful or open to debate
The scientist's questionable method raised concerns among peer reviewers.
O método questionável do cientista levantou preocupações entre os revisores.
2. An approach that lacks clear justification or follows dubious practices
Using questionable methods to gather data undermines the research credibility.
Usar métodos questionáveis para coletar dados prejudica a credibilidade da pesquisa.