Consider the Degree to Which the Text’s Content Is New or Surprising Within the Field
Once you have read through several sources on the same topic, you may see themes emerging not only within a source, but also across several sources. Perhaps you find five sources in accounting journals all focusing on the costs of compliance to the Sarbanes-Oxley Act, all suggesting that the costs are frivolous or unnecessary.
Have you wasted your time by reading five sources on the same basic topic? No! That helped you to understand the consensus that existed.
Should you ignore the sixth source that seems to contradict the others? Not at all! Being able to identify, in writing, the points of agreement and disagreement is a great way to start your own analysis of the topic.