Estimates Using Agile

Agile doesn’t have estimates, right? Well, that’s not quite right. It’s true that Agile embraces change, and does not attempt to define whole large projects up-front, but individual ‘Sprints’ are estimated, and sometimes multiple ‘Sprints’.

Of course, you can always give a big range for the estimate, but if all you are doing is expressing uncertainty, it will be of limited use.

There are a couple of other ways of approaching this. Both of them take a top-down approach, rather than a bottom-up approach, which attempts to break the project down into small components, estimate each one, and then add them up. Even if you do this accurately, it’s highly likely that requirements will change. It’s also very time consuming.

The approach we like to take at The Bridge is not so much an estimate based on a given set of requirements, but an estimate based on how long it took to build previous systems of similar size and scope. You need substantial experience in order to do this, but it has the advantage that it’s based on real data. It also incorporates the time that it takes for the toing and froing between developers and client, and the long tail (see my previous blog). For example, we are sometimes asked how quickly we can build a substantial website. In theory, maybe a month, but we never have, not only because of change, but because of the other factors influencing time to completion.

Another interesting top-down approach is budget-based estimating. This involves firstly establishing the objective of the estimate eg go/no-go for the project, add resources, allocate budget. The next step of the process is to estimate by requirement/feature from the top down, increasing granularity until a reasonable range can be provided. In the final step, some statistical analysis can be applied to give a probability of the functionality being delivered within a certain budget. Hence a decision can be made regarding the objective of the estimate.

If you’d like to discuss your website or software development options with The Bridge, feel free to call Lawrence on 02 9993 3300 or email