As thermography has evolved to become a widely used method for Nondestructive Testing, strategies and tools for interpretation of results have evolved similarly. While early stage efforts relied on direct visual interpretation of IR camera output, modern practice increasingly relies on signal processing to extend the range and sensitivity, perform quantitative measurement and enable automation. The most widely used methods, Thermographic Signal Reconstruction (TSR), Pulse Phase (PP), Lock-In (LI) and Principal Component Analysis (PCA) have all been demonstrated to outperform unprocessed results. However, the methods are quite different in their underlying mathematical approaches and in how results are presented to, and must be interpreted by, the end-user. In the past few years, several papers have attempted to provide comparative analysis of some, or all of these techniques. However, each paper defines its own benchmark samples and performance metrics, and defines the equipment and experimental procedure to be used for all of the methods studied. It is not surprising that results vary widely, and may be confusing to one trying to select an approach to implement. In this paper, we will evaluate several recent studies and compare their specific objectives, evaluation criteria, procedure, results, an analysis and conclusions, and identify strengths and pitfalls specific to thermography that should be considered in future comparative studies.