Final answer:
Feedback forms might be considered the least informative method for measuring training effectiveness, as they offer immediate self-reported measures that may not accurately assess deep learning or behavior changes compared to methods like observations or pre- and post-tests.
Step-by-step explanation:
The question asks which method is least informative in terms of measuring training effectiveness among surveys, observations, pre- and post-tests, and feedback forms. According to studies that include a 2003 study by Arthur, Bennett, Eden's, and Bell, as well as other literature on the subject, the effectiveness of training can be measured through various methods such as employee responses, learning outcomes through tests, behavioral observations, and results like productivity.
Feedback forms and surveys may provide a quick, self-reported measure of participant satisfaction or immediate response, but might not deeply assess learning or behavioral changes as effectively as observations or pre- and post-tests would. Therefore, feedback forms could be considered as potentially the least informative in terms of depth and application to actual job performance.