How best to collect data input to a Business Impact Analysis-BIA  in a hospital setting?
There are a number of methods to obtain the necessary perspectives and information which create the foundations of the BIA. These methods are common to any data gathering exercise and may include interviewing, questionnaires, and workshops. 
In an environment like a hospital, I think performing the initial tasks to create a BIA can best be approached using the interview method. Also, by concentrating on one functional group at a time, I believe it does a better job of preserving the integrity of the BIA. The interview method can and should be systematic with defined and repeatable questions in a particular order.  I suppose one could combine this approach and also send out an educational document to help prepare the interviewees for the session. This would be more efficient and give the employee the opportunity to do some research instead of just guessing during the interview. After all, we’re seeking accurate information, not just raw speculative data.
In my experience, questionnaires are useful to an educated audience, especially when review or repeat activity is necessary. However, to an audience of employees not accustomed to business continuity terminology or experienced in disaster preparedness, it may be a confusing or overwhelming task. There is quite a bit of overhead associated with the creation, distribution, collection, and interpretation of questionnaires . In particular, some essays are necessary to gather the most useful information. Analyzing and understanding essay response may require iterative interactions with the respondents. In the end, it almost becomes an interview of sorts. This approach is very time-consuming and I wouldn’t recommend it. 
The advantage of workshops is about saving time. The disadvantage, as any good interviewer would tell you, is that we see ‘group-think’ develop live during the session. This group-think certainly helps to build consensus, but can mask some of the more subtle yet possibly important data points.  Why does this masking occur? Well, the quieter folks just don’t speak up in a group setting, or what is heard sounds close to what a person was going to say and therefore the clarity goes unsaid. As more vocal strong speakers voice their ideas, others begin believing that what was said is correct, despite any previous thoughts they may have had. In my experience during search and rescue on the scene of dive emergencies we strive to separate witnesses in order to obtain ‘virgin’ untainted statements and observations. I believe the same is true of interviewing for the BIA. Last point on avoiding group think: If it’s decided to use the workshop or group meeting, a good solid facilitator will be key to successfully gathering the critically accurate information.
While each of the methods stated may work to obtain the necessary data for the BIA, it’s my preference that the one-on-one interviewing coupled with prepared, systematic questions, is the most useful approach.
 Business Continuity Institute. 2008./ “Good Practice Guidelines: Section 2:Understanding the Organization”. ver. 2008.1, pg 4
BIA: “…process for evaluating the impact over time of a disruption to an organisation’s ability to operate”;
 Cobb, Steven.” Weekly Instructor Commentary for Week Four”, Norwich University MSBC
 “Business Continuity Impact Analysis, State Office of Resource Management, Texas. Retrieved 9-28-09 from http://www.sorm.state.tx.us/Risk_Management/Business_Continuity/bus_impact.php
 Burtles, Jim. 2007. “Principles and Practice of Business Continuity: Tools and Techniques“, Rothstein Associates. Chpt. 5.
 Hallberg, Lillemor. “Some Thoughts About Interviewing“. Retrieved 9-29-09 from http://www.informaworld.com/smpp/section?content=a794904615&fulltext=713240928. Published in International Journal of Qualitative Studies on Health and Well-Being, volume 3, Issue 3, 2008., pages 130-131.
 Hansen, Robin. 26-JUL09. Overcoming Bias.com. “Who Will Fight Group Think“. Retrieved 9-29-09 from http://www.overcomingbias.com/2009/07/who-will-fight-group-think.html