Understand How the Evaluator is Selected.
Often, when the Court wishes to appoint a mental health professional to conduct a child custody evaluation, the Court requests that the attorneys agree to a particular evaluator or, if there is no agreement, that each offers up the names of a few who would be acceptable to their client, along with information about the evaluator, and the Court selects from among those presented. Find out the process that's used in your court and information about a number of possible evaluators such as training and experience conducting evaluations, training and experience regarding issues involved in your case, estimated time from start to completion (as well as availability to start immediately) and fee structure.
Read the Order AND the Stipulation
Often there is an order that an evaluation be conducted and THEN, when the evaluator is selected, the evaluator has a separate stipulation which spells out the terms, obligations and expectations of the evaluation process. You may not have a lot of input on the order but you certainly have some say in the terms of the stipulation. Often there will be a provision asking that you give up certain rights (such as therapist-patient privilege). It may be a good idea to do so in your case or not. These are things to discuss with your attorney but don't just sign off without reading what is expected of you.
Know THIS Evaluator's Process
There are certain basic components to a child custody evaluation. These include the evaluator meeting with you, meeting with the other parent, meeting with the children, observing each of you interacting with the children, speaking to others who are familiar with each of you as parents, etc. There are other components which some evaluators use but others do not (home visits, psychometric testing). Some evaluators do things in a different order than others. Find out from your lawyer what you can expect in terms of THIS evaluator's process. If your attorney doesn't know, have him or her find out. If you understand what to expect it will help reduce your level of anxiety during the process and you'll present yourself in your best light.
Provide Requested Information Promptly
Evaluators generally want to receive documents through your attorney (the attorneys have an obligation to share written information with each other so the evaluator isn't ever in the position of considering "secret" evidence). Some evaluators will ask for documents directly and will take it upon themselves to provide copies to the attorneys at the same time. In either case, providing the information promptly and completely will always be considered a positive to an evaluator. If you're asked to complete a questionnaire DO have your attorney review it before it goes to the evaluator. Sometimes parents are over-inclusive or under-inclusive and sometimes the tone in which they answer questions can be more negative than they intend. Having an attorney give the answers a "once over" allows the answers to be complete and truthful without being unintentionally sarcastic or mean (or even grammatically incorrect!)
Be Cooperative...but Ask Questions
When meeting with an evaluator, arrive on time, be neat and try to have reviewed any materials the evaluator has, and may ask questions about. If you have small children you're bringing along, make sure you're prepared as necessary (diapers and bottles for very little ones, snacks and toys for those a bit older). Part of what you're being scrutinized about is your ability to appropriately and gently maintain control of the situation...in other words, show that you're a loving parent. If the evaluators asks you things you don't understand, don't be afraid to look stupid by asking for clarification. You can ask thoughtful questions in a polite way.
Should I Pre-Take the Psychometric Tests?
Without a doubt, don't do this! While it's fine to meet with a mental health professional to understand the general nature of psychometric tests and the evaluation process in general, it will almost certainly do you more harm than good to try to "practice" the "right" answers on psychometric tests. Most of these tests are generally testing your personality or parenting knowledge and are being used to either generate hypotheses (something the evaluator will test with more questions) or to confirm or refute hypotheses (something the evaluators thinks may be going on with you but wants to see if that "guess" is right). Psychometric tests are almost never the most important part of a child custody evaluation and "cheating" on them by trying to second-guess them is more likely to make you look sneaky (and less credible) to an evaluator and to a judge.
Should I Change Anything About My Parenting Before the Evaluation?
While most evaluators will say they want to see you just the way you are, they also know that your house will never be cleaner than the day you know they're coming to do a home visit. It's human nature. If you have a serious problem that you're concerned about the evaluator discovering (particularly if it's been alleged by the other parent and it's true), deal with it. If you have a drinking problem, take steps now to combat it. Acknowledging problems and taking appropriate steps to correct them is generally a better strategy than trying to "hide" a flaw that everyone has already been talking about. What if you're a good parent but not a perfect parent? It will almost always help you as a parent to continually gain new information about parenting. It doesn't mean you were a bad parent before. Read some books about parenting children the age yours are now (or, better yet, ones a little older so you can show you know what to expect). Take a class at the Y. It shows you're invested.