Determining the appropriate source(s) for your speech involves more that just identifying something that is on-topic. It involves a critical analysis encompassing all aspects of the source, its context, and how you plan to use it.
SIFT is a handy acronym to help you sift through all the information may find on your topic. It outlines a four-move strategy for which you would:
- Stop. Remember your purpose. Ask yourself what you already know about the creator/author or the source.
- Investigate. Know what you are reading about before you read it.
- Find. Find coverage or consensus on the primary claim of your source before trusting it.
- Trace. Trace information back to the original source to re-contextualize it and gain a better understanding.

The concept of SIFT comes from Mike Caulfield. It is reused here under a Creative Commons license.