trend studies

Trend studies are valuable in describing long-term changes in a population. They can establish a pattern over time to detect shifts and changes in some event. Marketing companies, for example, compile trend studies that chart fluctuations in consumption levels for a certain product. Among others there are two important advantages of trend studies.

Flexibility

One advantage of trend study is that they can be based on a comparison of survey data originally constructed for other purposes. Of course in utilizing such secondary data, the research needs to recognize any differences in question wording, contexts, sampling, or analysis techniques that might differ from one survey to the next.

Cost effectiveness

Since trend studies allow researchers to use secondary data, it saves time, money, and personnel.

Disadvantages

Trend analysis is to provide descriptive trends of some topic in a certain period of time. Therefore, there is less concerns on internal validity because it does not aim to provide causal inferences as in the case of experimental studies or some penal studies. However, trend analysis also suffer from similar threats to validity. If data are unreliable, for example, false trends will show up in the results. If trend analysis is based on inconsistent measures, the results will be biased just like instrumentation threat can bias experimental studies. That is, changes in the way indexes are constructed or the way questions are asked will produce results that are not comparable over time. In the worst case, the changes in measures alone can produce a pseudo trend which might fool both the researchers and readers.