The Case For Agile Over Waterfall
This article came about as the result of a recent trip I made to a customer. I was presenting on TFS and made the, oft repeated, statement that Agile is better than Waterfall. Now I have to admit that I have never really had anyone challenge me on this assumption since most of the people I know just accept this as truth. On this particular day there were a couple of project managers in the audience and they were none too pleased about my assertion. For the rest of the hour, we went back and forth on the issue. Following are a few of exchanges to the best of my recollection:
Exchange 1
Project managers: “You can’t say that agile is better than waterfall, it simply isn’t true.”
Me: “I have twenty years of evidence backing up my claim and I have personally seen it work this way.”
Exchange 2
Project managers: “Well, we have government regulations we deal with and you just don’t understand what we do here.”
Me: “I have [another customer] that has to deal with HIPPA requirements and they use Agile so I don’t think your requirements are that strict, are they?”
Exchange 3
Project managers: “We don’t use pure Waterfall we use a modified version.”
Me: “So..you’ve already modified your methodology because it’s inadequate. Why not finish the job?”
Essentially the arguments went on from there but were just variations on these three exchanges. To be fair, I tried to explain that I believe Waterfall has it’s place in many, many areas just not in software development but this argument fell on deaf ears. So it got me to thinking: “Am I right?” I had looked at some evidence years ago and had proven it out myself on countless occasions but was that still the case all these years later? Did Agile methodologies still hold sway over Waterfall? Did the evidence prove it? To that end I have assembled evidence for myself and for anyone else who has to fight the Agile battle. Please feel free to add your own evidence (pro or con) in the comments.
Please note that I deal in empirical data. Period. I can find any number of people (including myself) who have had good/bad experiences with Waterfall and good/bad experiences with Agile. On the main, I’ve found Agile to be better in the situations I have dealt with but I have seen plenty of people swear to Waterfall the same way. To even the playing field I have to go to objective data as the measure rather than feelings. The data I found shows many data points but there are two that I think are vital for people to understand:
- Overall, Agile methodologies are better for software development projects than traditional project management (Waterfall).
- Even Agile projects fail; having a superior methodology is no substitute for a good team and solid project discipline.
Waterfall Over Agile
I looked for any empirical data that would show traditional project management (Waterfall) beating Agile methodologies for software development. After several hours I gave up. I don’t know if it exists but if it does the data showing Waterfall beating Agile is very hard to find.
Agile Over Waterfall
The exact opposite is true for Agile being better for software development than traditional project management. There were too many studies to include so i decided to focus on one of the key studies that would be most appealing to management. To that end, I found an excellent article written by Dr. David F. Rico, PMP, ACP, CSM entitled “The Business Value of Using Agile Project Management for New Products and Services” (https://davidfrico.com/rico-apm-roi.pdf). It is an extremely concise and well documented survey of data in support of Agile and is a “study of studies” that really summarizes the Agile impact. I suggest you read the entire article but below are the most compelling pieces of data showing improvement of Agile over traditional project management within several studies:
https://davidfrico.com/rico-apm-roi.pdf
In the same article Dr. Rico also mentions the 2008 Maryland study that “[…]developed a database with over 153 data points on the costs and benefits of agile project management from 72 studies.” [Rico, D. F. (2008). What is the ROI of agile vs. traditional methods? An analysis of extreme programming, testdriven development, pair programming, and scrum (using real options). TickIT International, 10(4), 9-18]:
https://davidfrico.com/rico-apm-roi.pdf
Additionally, in 2009 there was another study that examined the “[c]ost and benefit metrics, models, and measures were developed based on 52 data points from 32 studies.” [Rico, D. F., Sayani, H. H., & Sone, S. (2009). The business value of agile software methods: Maximizing ROI with just-in-time processes and documentation. Ft. Lauderdale, FL: J. Ross Publishing.]:
https://davidfrico.com/rico-apm-roi.pdf
Naturally there are many, many more articles on the benefits of Agile. One other one that springs to mind is Ben Linder’s article entitled, “Evidence of Success of Agile Projects”. (https://www.infoq.com/news/2012/11/success-agile-projects). Linders cites references to other studies that have shown Agile project success as well as guidance for implementation. Feel free to add you own favorite study in the comments section and, if you have a study that shows Waterfall beating Agile I will gladly add it to the main article for balance.