Part of your practice—whether it focuses on civil or criminal litigation, internal investigations or even business transactions—will involve interviewing witnesses who will inform your matters. Here are a few tips, gleaned from my experience in speaking and listening to witnesses in offices, roadside diners and detention facilities, for conducting effective interviews.

• Know your witness.

Read all pertinent documents before speaking to a witness. Conducting a thorough document review beforehand will ensure a thorough interview. It also will help structure your outline of questions (see below). Regardless whether there are documents available, do background research on the witness. If you have the resources, obtain a report on the witness from a database service like Accurint. At minimum, plug the person's name into an internet search engine. You can learn a lot about someone through Google, especially if the person is prominent in a professional field or has a substantial online presence for other reasons. Once, while preparing to interview a child psychologist, I learned through a basic online search that the witness had been disciplined professionally and sued civilly for having an affair with a barely legal patient. That information at least arguably tainted the diagnosis she rendered in the instant matter.

• Put questions to paper.

Writing or typing a list of questions is an essential part of preparation. Even if you do not rely on the outline during the interview, having prepared one will ensure that your presentation is organized and that you cover all the key areas of inquiry. I tend to write my questions verbatim in an initial outline, so that I can focus on the wording. I will then distill that into something shorter and more usable.

• Consider logistics.

Who will conduct the interview? If you are interviewing a potential trial witness, you likely will want to employ an investigator to ask the questions so that you can call that person to impeach the witness if necessary. Where will the interview be? Home court advantage may be helpful, especially if you intend to use a lot of documents. However, the witness may be more comfortable at her office or even at home, depending on the circumstances. Who, if anybody, is taking notes? Writing as someone is speaking can form a barrier. If feasible, consider enlisting a colleague to take notes so that you can engage the witness.

• Be adaptable.

Every interview is different and must be treated as such. If you are interviewing, for example, a potential expert witness in an office setting, it likely will be appropriate—and indeed necessary—to use an outline and take notes. But if you're in out in the field, cold-calling witnesses of a crime, it probably will be more effective to eschew those formalities, especially if the interview will cover a small number of topics. Be mindful of time and manner of dress. If you know (or suspect) the interview will be brief, front load the key questions. Depending on where you are and who you are speaking with, it may be off-putting to wear a suit.

• Connect.

If the witness does not like you, the interview will suffer. So your first and most important task is to connect with the witness. Smile. Make eye contact. Be empathetic if the situation warrants it. Express appreciation for the witness's time. If you intend to take notes or record the interview, ask the witness's permission first.

• Listen before you read.

If you rely on an outline, do not let it prevent you from listening to what the witness says. Through their answers, witnesses often reveal areas of inquiry that you had not considered. If you are focused on moving through your outline and asking the next question, you will miss opportunities to learn more about the witness and enrich your understanding of the matter.

• Ask to follow up.

No matter how well you prepare, you likely will neglect to pose a question that you later will wish you had asked. It is also possible that your understanding of the witness's role in the matter will evolve after the interview. Accordingly, end the interview by asking if you can follow up if additional questions arise and get the witness's contact information.

• Process the information.

Convert what you learned to work product as soon as you can, even if you took notes or recorded the interview. I prefer writing formal memoranda because putting the facts into a narrative helps me to understand and remember how everything fits together. Plus, it is easier to make use of a memorandum than hastily scrawled notes months or years after the fact. An effective memorandum will not only recount what the witness said, but also provide your impression of his demeanor, credibility and candor.

Douglas E. Roberts is a senior associate in the government enforcement, compliance and white collar litigation and qui tam practice groups in the Philadelphia Office of Pietragallo Gordon Alfano Bosick & Raspanti. He has tried numerous criminal and civil cases to verdict in federal and state court.