Final answer:
Limited control over data quality is a disadvantage of secondary data because researchers rely on the scope and accuracy of pre-existing data, which might not meet the specific requirements of their study.
Step-by-step explanation:
A disadvantage of secondary data is limited control over data quality. Secondary data is essentially data that has already been collected by someone else for a different purpose, so when researchers use this data, they are restricted by the scope, accuracy, and reliability of the original data collection. They cannot ensure the data meets the specific standards or conditions that their own research might require. This can be particularly problematic if there is no method for verifying the accuracy of the data, or if the data does not match the precise requirements of the new research question.
In contrast to primary data collection, which can be time-consuming and expensive, secondary data is generally quicker and less costly to collect, since it involves the use of already published information. However, the tradeoff is the lack of control researchers have, which may make it difficult to answer their specific research questions satisfactorily. Issues such as inconsistent data sets from different sources can also pose challenges for comparing and analyzing data effectively.