A researcher must always evaluate secondary information carefully; however, the researcher does not need to ensure the evaluation is?

subjective

Explanation:

When evaluating our information sources during research, one must ensure the information are not outdated. It is also very important that we use data that are quite relevant to the work we are doing, directly explaining what we are doing. We should also seek information sources that seem very accurate and devoid of all forms of impartiality.

Having said all these, the issue of subjective nature of research is key. Any information deemed "subjective" usually contains write-ups that show opinions of the writer or persons formulating the data. It could also have different emotional undertone and personal judgment. A good researcher should not try to know if his or her information meets this criterion of being subjective.