A methodological approach refers to the specific way or method that someone uses to study or solve a problem. It is a systematic and structured way of approaching research or inquiry. Full definition
The studies included reflect a range of methodological approaches, with preference given to studies with the most rigorous approaches (experimental and quasi-experimental designs); qualitative studies are included when they are the most relevant to the specific practices. (leaplearningframework.org)
Climate change studies have used various different regional definitions, depending on the character of the problem considered and differences in methodological approaches. (ipcc.ch)
Some of these problems are a logical consequence of different national circumstances and data, and some are a consequence of different methodological approaches. (usask.ca)