At last something reasonably sensible here, from a big Indian services company regarding Scrum. I say reasonably, because the conclusions arrived at are largely correct, whereas a couple of points made in support reveal an underlying thinking which is slightly questionable. I shall proceed to answer the Q of an “ideal” sprint length before returning to take apart the article referred to above.
Most Scrum teams use two week sprints and a few even one week sprints. In some organizations where iterations have been about 3 months, or more in length or even worse a classic waterfall (Before Scrum) teams have a real problem starting with two week sprints. Much of this is in the mind. It is common for people in such projects to feel (or even ‘know’) that nothing can be achieved in two weeks. So, there is considerable reluctance to pick a two week sprint. Now the question is what should be the length of the first few sprints?
Something of a storm in a tea cup, is how I see it; There is no doubt in my mind that a two week sprint (with suitably small units functionality as backlog items) is what the doctor ordered. However in these times of diminished authority, quite a few people seem to duck clinical instructions, let alone heed good advice. So, a logical (at least superficially) decision is made where in a much longer sprint length is chosen. If it were of four weeks, that is still within the rules of Scrum, but not a good choice. I’ve even seen a two month sprint taken up as how to proceed with Scrum, which really is a marvelous illustration of how NOT to do Scrum. Basically the underlying problem is once again the lack of realisation that Scrum is really a rather radical departure from the traditional waterfall way of completing projects. Not an embellishment of the old ways of working with the latest jargon, minus the real intent, which in turn simply results in Scrum-but.
So why is a long sprint three weeks or more a problem?
1) Loss of feedback (course correction opportunity): Essentially there are fewer opportunities for the PO and functional stakeholders to get to know the growing system and provide feedback.
2) difficulty of holding on to the “NO CHANGE RULE”, particularly the part where the sprint goal has to be held fixed; i.e no changes to the stories picked up by the team at time of SPM (sprint planning meeting) are to be allowed, is increasingly difficult to maintain as the length of sprint increases.
3) Effectiveness of retrospective: One of the most important environmental conditions for a good retrospective is that people should remember what happened during the sprint. The only other even more important condition is openness and assurance of safety. Most people cannot recall many (unremarkable, but important) details beyond last week. That’s a two week span. So once a sprint is longer than two weeks, we have a memory retention problem, unless the team maintains a detailed activity log. Yeah right!
4) Reduced planning effectiveness: As the time horizon increases, it becomes more difficult to plan for the entire timebox. It is substantially more difficult to plan a longer period of activity realistically than a short one. A weakness of long term planning ability exists in most software project groups.
In fact all the above means, it is imperative that teams improve their ability to plan (a major underlying factor is estimation, but that is another long story), make progress, correct and then build upon what has already been achieved. Basically do the “inspect and adapt”. So in a way more opportunities the better. Hence a shorter cycles are better.
OBERVATIONS on the Cognizant article
(Overall I think the article is well written and has many aspects covered well)
Pl refer to table in the article.
A flawed line of thinking here is “Adaptation to uncertainty in story creation”, which talks about stories crossing sprint boundaries. This assumes that stories are going to be large. Actually they can be quite small. Short cycles can be handled if the organisation and team learn to break functionality into sufficiently small blocks (here is an interesting thought on this matter). This is a skill that needs to be developed, and time after time many people have discovered that the most complex application can be broken down into block that need a couple of people to work on it for a couple of days. So ideally for a two week sprint a team of about seven people about 8 to 15 stories (or sub-stories, if you prefer) can be picked up.
An argument made by armchair planners against short sprints is that the overheads will take up a greater percentage of time as a whole (as possibly being hinted by the above article; see 32,16,11 and 8 days). However for shorter sprint the planning, review and retrospective times will also come down; Of course time spent arranging for these meetings may go up, since number of meeting per month will increase. However this is a matter of habit, if everyone soon gets used to weekly meetings (each meeting of shorter duration) this will actually be a negligible overhead, with a tremendous amount of learning and correcting being generated. So a shorter sprint is better than a longer sprint. So item 1 “Ceremonial days” in the table isn’t quite right.
The other (more worrying) point made is that about procrastination; Use of sprint burndown chart correctly will actually circumvent this! In fact very long sprints may just increase pressure on the team since there is a real possibility that team will struggle to meet sprint goals towards the end of a sprint. There is a real danger of falling into a serious waterfall mode every long sprint. Teams don’t seriously examine their way of working and change to get as far away as possible from the waterfall. In fact in this matter the article seems to lie on a resource (read people) utilization perspective and the worry that people are not going to be busy all the time, easily confusing activity for progress; which is fairly anti-Scrum in approach.
Another issue with the article is the point about “minimum number of days spent testing”! This is really puzzling. Is less “testing” days better, or worse!?! I’ve no idea what this article considers better, let alone what the thinking behind this is. In reality it depends heavily on the context of the project, the abilities of the team members, automation involved (rightly or wrongly)… so many ifs and buts. In fact Scrum does not even attempt to prescribe this.
So the main root point in favour of a long sprint is the comfort of the team and managers involved coming from a waterfall habit! This is really a question of willingness, understanding and realization of the people involved in the project. Not something to be sneered at, maybe a coach can help. He/She must show sensitivity to this, and do all possible to show the team how to break down user stories into smaller blocks of functionality.
In closing…everything else points to shorter sprints. A two week sprint is strongly recommended and indeed used by many, many successful Scrum teams.
PS: The points made above may seem like a merciless slating of a deeply flawed article, but not so, the article itself makes many good points from a certain level of Scrum understanding. I think it analyses the various factors of making the sprint length decision fairly well. Here I am simply attempting to provide a deeper understanding of how to think through this matter.