If I had a dollar for every time somebody says: "We have to deliver fast, lets go Agile", I would have about 20$ already. This does not sound like much, but this is the REAL number of times I have heard it. Moreover, nobody has ever said: "We have to deliver fast! Lets do good old waterfall !!!"
Well, are all those people wrong? YES!
The results just came in. Agile process is not the fastest development process. Who come in first you ask? Waterfall.
How come? It is actually simple. Lets say that you have 100 boxes that you have to move to another place. You have a team of 10 completely identical people at your disposal. They are identical just to make the calculations easier, not because they are cloned or something like that. Every person can move one box in one minute.
How agile development, sorry, box moving looks like.
- Short sync and planning (1 minute): you take this box, you take this box and etc.
- Move the box - 1 minute.
- Retrospect (1 minute): how was your moving? Any insights?
- Repeat until all boxes moved.
There will be 10 such iterations, 3 minutes each. In total this will make 30 minutes.
Now, lets do waterfall.
- Long planning (10 minutes): you take those 10 boxes, you take those 10 boxes and etc.
- Move the boxes - 10 minutes.
- Retrospect - 1 minute.
Total time: 21 minutes.
Now, if you think that this example is not fair, then you are right.
Usually, agile will spend much more time shuffling already moved boxes as they are not in the right place. Yep, agile processes excel at re-work. Since the goal is to make the minimal working version at each iteration, many times it is not the optimal one. Then it has to be re-structured and re-done. This will add more time, but the process is enjoyable and team is having a great time at all those stand-up meetings.
Why do agile then?
The answer is simple: because you want to be agile (this is me trying to be funny). Notice: not fast, agile. Lets say that 12 minutes after the start product manager decided that boxes have to be moved to a different location.
- Agile process can adjust on the very next iteration, i.e. every 3 minutes. Total time will be: 12 minutes (before the change) + 30 minutes (to move the remaining boxes and those that were already moved) = 42 minutes
- With waterfall you will have to re-start the entire process when it ends. This is basically because there is no process to stop the waterfall. Total time will be: 21 minutes (to complete the first iteration) + 20 minutes (retrospect and blaming one another) + 21 minutes (move the boxes to a new location) = 62 minutes.
Sometimes, being agile actually gets you faster to the ending point. This happens when requirements keep on changing or when you are running in zig-zags under fire.