Q: What is the meaning of 'revisited study'?

A revisited study is in fact exactly that: a topic that had been studied earlier and is being studied again. And yet, it is not mere repetition; it is not as though the same experiment or study is being repeated merely to get more data. Typically, in revisited studies, it is the methods that change while the objectives do not. The change is prompted by newer techniques, more sensitive instruments, larger or more representative samples, and so on. Thus, each time you visit a study, you learn something new because of better instrumentation or a different approach, although the purpose remains the same. Revisited studies are quite common and keep widening our knowledge, taking advantage of the progress in instrumentation, statistical methodology, big data, and so on.

Consider an experiment to ascertain the effect of regular physical exercise on people. We all know that running long distances regularly at a steady pace improves your stamina. But what exactly is the mechanism behind this change? With little instrumentation available, all the experimenter can say is that, over time, the same distance covered at the same speed left the subjects less exhausted than before; in other words, the degree of perceived exertion decreased. With more sophisticated instruments, perhaps one can show that the volume of air being inhaled – the lung capacity – increases because of repeated practice. As science continues to advance, later researchers may find that the hemoglobin content of blood also increases.

Take gender bias in experiments: although subjects in most medical studies tend to be men, the findings are generalized to cover both sexes. However, with greater care being exercised to make the findings representative, it turned out that many drugs work quite differently for women: the ‘revisited’ studies thus have thrown a fresh light on earlier findings.

Biotechnology is yet another field that offers ample examples of revisited studies, as does physics. Advances in nanotechnology have served to confirm, contradict, or refine many of the earlier studies on atomic and subatomic particles. In plant breeding, to study the differences between the parents and the progeny, early researchers had to collect pollen from one plant and hand-pollinate flowers growing on another plant, then wait until such cross-pollinated flowers turned into fruit and produced seed, and finally sow those seeds and wait until new plants emerged. Such studies are now routinely revisited by using DNA and introducing selected bits of it into not only into other members of the same species but even into totally unrelated organisms. For example, genes from animals are introduced into plants and vice versa: the genes from bacteria that infected worms feeding on plants have been transferred directly into the plants themselves to control the worms.

Hope that helps!

Related reading:

• Types of qualitative research methods
• How to choose the research methodology best suited for your study
• How to write the Methods section of a research paper