Conducting an investigation into the aspects of the case demands attention to detail, planning, and care in the steps you take. As the expert in your field, determine what you need to have and what you need to do before you can draw any opinions. You have to identify the facts you need to know before forming any opinion in the case. For instance, you must assess:
*  what you need to find out
*  what you need to test
*  what you need to reconstruct
*  what mathematical equations you need to formulate
*  who you need to interview
*  what documents you need to read
*  what software you need to use
*  what information you need to compare
Words like ‘painstaking,’ ‘methodical,’ ‘meticulous,’ ‘step-by-step,’ and ‘careful’ should describe your approach. By and large, begin with having simple, factual discussions with your attorney, and subsequently, your attorney’s client. These discussions may lead to documents either now filed or already collected by the attorney.
Your discussions with the attorney’s client may lead to finding or receiving additional documents to read, or to additional persons with whom to speak. As you know details of the case, you will collect additional facts. Some of it may have now been filed as part of the case, and some of it may be accessible to the persons with whom you meet and speak. At times, you will visit the site involved or make observations of equivalent machinery or systems at another site.
You must decide what facts to Consider and what facts to ignore. Federal Rule of Evidence 703 demands that the basis for expert testimony must be facts that is “reasonably relied on by experts in the particular field in forming opinions or inferences.” The attorneys in your case are not experts in your field so, by definition, they are not competent to expertly evaluate the evidence to decide what parts of it may or may not be relevant to your opinions. Attorneys will sometimes show you only a subset of the technical facts in a case. When they do that, they undermine their own case and they undercut your likelihood of accomplishment during testimony.
Make sure to ask for all on point information, regardless of whether others might call your request irrelevant. Obvious technical information that bears on the case is relevant. So are any documents that discuss technical data, regardless of who wrote the documents. As your understanding of the case progresses, you may expand the scope of your data requests. This may come about as you learn more about various events and participants, or it may come about after reviewing other discovery materials.
In a complicated case, many boxes of evidence may exist for review, frequently stored at the attorney’s office. occasionally the boxes are labeled, and occasionally an index exists that clarifies what documents and materials are available. You should always look through the index or the boxes to decide what material to review in detail and what to reject before proceeding with opinion formulation. The room where the attorneys store these boxes of evidence is colloquially referred to as the war room.
Asking your attorney and client for additional details and data can save you the time or cost of finding it. If you cannot secure what you need directly from your client or attorney, you should look further and continue your research and investigation with other sources.
Your testimony is stronger if you can honestly say that you personally assessed the total available facts and determined what was relevant and what was irrelevant.