i. A major advantage in the use of secondary data is that it is far more economical as the cost of collecting original data is saved.
ii. Another advantage is that the use of secondary data saves much of the time of the researcher. This leads to prompt completion of the research project. However, in some instances a researcher should be prepared to spend considerable time combining secondary sources in order to acquire the most useful type of information.
Iii. Another benefit of secondary information is that it can assist in eliminating information gaps and be useful in clarifying and formulating the problem at hand.
iv. As the researcher explorers the availability of secondary data relevance to his project, he finds the process former that his understanding of the problem has improved. He may even have to change some of his earlier ideas in the light of secondary data.
v. Secondary data can provide a source of comparison with primary data and thereby aid interpretation and evaluation. They can act as baseline data or at least as a benchmark from which the researcher can continue to conduct primary research studies.
vi. By using such data the researcher can also gain access to much larger samples and to subjects or respondents who could not be reached by other methods.
Disadvantages of secondary data.
i. The unit in which secondary data expressed may not be the same as is required in the research project. In that case, secondary data cannot be used.
ii. Even if the units are the same as those required by the research project, it may just be the case that class boundaries are different from those desired.
iii. Again, one does not always know how accurate the secondary data are. Indicate degree of inaccuracy is high the use of such dubious data would undermind the usefulness of a research study. In most cases, it is difficult to know with what care secondary data have been collected and tabulated.
iv. A severe limitation in the use of secondary data is that they may be somewhat out-of-date. Obviously, the usefulness of secondary data declines progressively as the time goes by, and there are finally useful for only the historical purposes.
