1) To address a question and answer with important information and an explanation of its impact
A social worker may want an exploration of the client's needs and prognosis, or a prediction of their risk to be violent, abuse children, or relapse to abusing substances. A neurologist may want it to determine the extent to which neurological changes are seen in real life behaviors. A medical doctor, or a lawyer, may want to know to what extent a client is turning emotional distress into physical distress, while a vocational counselor wants to know a client's strengths, weaknesses, and best placement in the job market. A judge might want to know which adult is the better parent in a family. Some employers will want to know how well a person can handle stress, if they should be allowed to carry a gun, or if they are emotionally sound to serve as a counselor or aide to troubled people. Some clients and therapists simply want to understand their client better.

2) To serve as the record for a case
Sometimes the Psychological Evaluation is the only record that's really available on a client. A neurologist might want a detailed documentation of functioning to judge later deterioration by, while a court might want documentation of a client's functioning before making a decision of what they are capable of doing or not.

3) To re-frame the client's case and issues
Sometimes the most helpful thing you can do in a psychological report is explain the client's resistance, highlight some of their struggles, and basically indicate that they are human even if they don't appear it at times. This isn't a very specific goal, but humans write about humans for other humans to learn.

For Adults:

 

It should be noted that "intelligence" is defined by the test used here as the global capacity of the individual to deal effectively with the environment. IQ tests sample skills in select areas in order to estimate overall intelligence. Thus, IQ scores and intelligence are not the same thing. The scores obtained here should be used to predict the client's educational and vocational functioning. Use of these scores beyond that should be approached with caution, as cultural values, educational opportunities, physical health, emotional troubles, and living environment can all impact scores.

For Children:

 

The reader should note that intelligence is often defined as the global capacity of a child to deal effectively with their environment. IQ tests sample skills in select areas in order to estimate current intellectual functioning. Thus, IQ scores are not the same thing as "potential" or "intelligence." However, when part of a psychological assessment, results can be used to understand adjustment, identify learning needs, and predict educational success (i.e., years completed in school, grades, and vocational level). Such predictions, however, are impacted by poverty, bilingual environments, experiences with parents, and stability of the home life. Results are considered to be relatively stable for one year, and use of these scores after that is not recommended; changes in the child's home, educational setting, and physical health can significantly change these scores. Use of these scores to estimate a child's functioning in others areas should be approached with caution, especially with bilingual children or children of cultural minority groups.