Methods of estimation
Building a reasonable schedule or estimate is based on two complementary methods: analysis and analogy. Using analysis we divide a project into a number of more comprehensible subtasks which can be estimated easily, and then aggregate these estimates into the final one. For example, if we want to implement a microblogging service, we need to break down the functionality into the smallest possible blocks: user registration, login, sending posts, looking at the blog roll etc., and then weight up how long it would take to implement each one.
Analogy is completely different style of thinking. Here we base the estimation on our previous experience: if we have done a
Drawbacks
Okay, so what's wrong with those methods anyway?
The problem with analysis is that it requires a very detailed realization of what exactly should be done. Planning in general words is fooling yourself ? I've seen a lot li ning futbol of seemingly tiny details that completely changed my view on how to implement the project. Even if from a layman's point of view tasks such as verifying that a program cannot fall into infinite loop, checking with 100% confidence whether user opened email or merely programmatically changing image on iPhone lock screen seem perfectly natural, in fact they are impossible due to fundamental, technological or political reasons. So to build a reliable estimate ideally one need to li ning futbol think over every little detail in the project. No wonder it can take a lot of time, but the real problem is sometimes we simply do not have enough information to make such an elaborate estimate.
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