A lot has been said and done about Software estimation – books have been written , techniques have been developed and blogs have been published. I am no estimation guru and I am not writing this blog to enumerate estimation techniques. However I would like to make a strong point on off-the-cuff estimates. Never do it . I have almost always been burnt by off-the-cuff estimates , whenever I have done it during my career. We all fall into the trap of doing it one way or the other. Several scenarios contribute to developers making those impromptu estimates ….one I have seen is when some non technical Stake holder comments – “that’s easy right ? that can be done in 10 minutes” . Off you go…the statement can play on your psyche and make you say “Yeah sure…I should be able to finish it quickly ” – even though you didn’t admit to 10 minutes , you almost committed to doing it in a very very short span without analysing it .
We all have a tendency to say what others would like to hear, however we all very well know that in case of Software estimates we better not do that – ” Things always take more time what they seemed like they would take in Software development” . I have heard so many developers admit to it and yet not take the time to go through detailed estimation effort. In most cases estimates are taken as commitments by Managers or Stake holders. If you have given a development plan with estimates on it , the rest of the group will take it as a commitment. So not only is making impromptu/unprepared estimates a big mistake , eventually it can start proving you incompetent and inexperienced. A great sign of experience and maturity in a Software professional is that he/she takes all the time that can be in analyzing the problem to the lowest granularity level and then measuring the effort . All small efforts should be taken into account and unknowns should be listed. If you have to do that you cannot give off-the-cuff estimates , no matter how trivial it may seem .
Trivializing development tasks is a very common thing in software engineering and it is done by experienced software professionals as well. Most people find it difficult to handle situations where their tasks get trivialized by others – a common retort is “Why don’t you do it then?” which is very unprofessional. Or a lot of programmers eager to make the Stake holders happy succumb to the pressure and give very aggressive estimates. Both reactions are destructive. The best policy is always to say -“I need to go over it in detail before giving any estimate”. According to me there are no Trivial tasks in software engineering – there are always hidden consequences and unknowns. These can come to haunt you later so it is wise to be cautious in making any statements which will be taken as commitments . Estimation comes with experience and unfortunately we all learn it the hard way – real world programming teaches you to realize , “It’s not what it seems at the first glance” .