How many people should be involved in requirements elicitation? A question from one of our readers via email.
Hi Scott, in the last months I faced the issue of managing the requirement elicitation phase in an Identity Management project. I have a very simple question. In your opinion how many people should do the interview process against the customer ?
In my experience one person is not enough even if the interview session is electronically recoded. I have observed the two heads are much more better than one since two different points of view are captured from the Voice of the Customer.
I’d be happy to hear your opinion on this.
Thanks for the great question! I’ll turn this into two questions and try and answer them both.
- How many requirements gatherers should gather requirements from the subject matter expert (SME)?
- How many SMEs should be providing requirements to the requirements gatherer?
How Many Requirements Gatherers?
A simple question deserves a simple answer: two if you can afford it, one if you can’t. Feel free to skip the rest of the article. :)
The success of requirements elicitation hinges on our ability to listen effectively. Active listening allows one analyst to get the same information from an answer that two people (who hear things differently) would get. The bigger benefit of adding a second person comes from asking questions. Two people will identify more loopholes and corner cases, will ask questions that uncover unspoken requirements, and otherwise improve the quality of the information gathered. Will they identify twice as much? No. There’s a law of diminishing returns at play. And the greater the skill of the analysts, the more overlap there will be in the questions they each ask. A third analyst won’t add much at all, and will run the risk of getting distracted and not really contributing anyway.
Having two interviews, each by one analyst, each of a single SME, will probably unearth more requirements than if both analysts interviewed a single SME once in a joint session. When the schedule/budget is tight, use this approach for the most efficient requirements gathering. When efficiency is not a driver, then doubling up the analysts will get better data – just not twice as good.
How Many SMEs?
Another valid question is how many SMEs to interview in a single session? I think two is an ideal number. One SME will unconciously gloss over details, that a second SME will catch. The two SMEs can debate contentious points, and correct and help each other. If both SMEs aren’t available for the same meeting, meet with them sequentially. Have the second SME review the requirements that were documented with the first SME.
Again, there is an efficiency issue – do we double up the SMEs (and the cost of them), or do we work with them sequentially? Doubling up is better, but again, not twice as good due to diminishing returns. A third SME is likely to cause the conversations to devolve and become much less effective – even if uncovering more details, the overall process will be less efficient.
Other Factors
There are a couple other factors that have more of an impact than perfectly optimizing the number of attendees. The best way to improve requirements gathering is by increasing the experience/skill of the business analyst. Check out the factors at the end of this article on estimating requirements gathering for more details. Similarly, SME aptitude plays a role.
As analysts, we have to be able to wear a bunch of different hats. We are talking to SMEs about their expert domain. We are validating that our requirements are attainable, by applying our knowledge of the IT world. And we are making sure that we focus on the most valuable requirements by applying some understanding of ROI. Basically, we have to be comfortable operating in all three domains of expertise.
If we find that we need to include more people in our meetings to get coverage across all the domains, that would supercede the “two is better than one, but one is more efficient” arguments from above.
Conclusion
We have to make sure we get coverage of each domain of expertise. One person is more cost-effective than two. Two people will elicit better requirements than one.
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