1. in general, a judgment of the quality, worth, importance, or value of something or someone.

2. in research, a systematic process of obtaining information from participants and using it to make inferences or judgments about them. In a clinical context, this process is known as a psychological assessment.

3. in animal behavior, an evaluation of an individual based on its behavior or communication signals. A potential rival might use the degree of vigor and complexity of a male’s song or the intensity of its plumage color to assess the probability of displacing that male. Similarly, a female might evaluate the relative quality of different potential mates in mate selection. Assessment may be a major function of animal communication.