Software Estimation – Art or Science? – Part 2

In the previous post, we looked into different aspects of software estimation,

  • Types of Estimation
  • Estimation Process
  • Common Pitfalls
  • Role of estimation tool and how it can benefit organization in long run

We will continue from there, and in this post we will look into benefits of capturing organization’s historical data and type of analytics you can do over that historical data, that will help you take informed decisions quickly and with confidence.

First and foremost benefit of capturing historical data – so that you can compare your estimate with your historical data. People will argue that each project is different and so each estimation is different. But that doesn’t mean you can’t compare. Estimation starts with breaking down scenarios into smaller requirements and then estimating it either through top-down or bottom-up approaches. Within estimation, lot of other environmental and technical factors also play a role, and these vary based on company/team structure, organizational capability, and others. So comparing estimates is not just about comparing requirements one on one, but it include lot of other factors too, which can be very unique to your organization/team. You can always categorized projects into different categories, such as based on industry or technology. And you can compare your estimate within that particular category, that will narrow down your comparison and be more specific.

Coming to analytics, it can be of different types, but personally I like following two,

  1. Project Size Vs Duration
  2. Identify Impossible Zone

Project Size and Duration

In this, you compare Duration of the project Vs Size of the project. Unit of size you can standardize based on your organization. It could simply be an Effort, or UCP (Use Case Point) or FP (Function Point) or any other unit based on your estimation methodology. Duration is straight forward, it’s a time span, either in hours or days or weeks or months.

Size Vs Duration is the simplest of the comparison, but it provide lot of information, such as,

  1. Minimum and Maximum range of deviation from the organization productivity, i.e. size vs duration.
  2. How far your current estimates is from your organizational historical productivity.

Compare with Historical Data (Duration Vs Size)

Identify Impossible Zone

If you have been involved in any pre-sales, one of the most common request comes from sales team or customer is to reduce overall duration of the project by compensating it with number of resources. But the question is – how much you can reduce the duration? In project management terms, you first create project plan, identify critical path and that will give you the minimum required duration. But during pre-sales, most probably you will not have that luxury to create detailed project plan and come up with critical path.

So how do you identify impossible zone?
Here also, the historical data and estimation tool can play a big role. Based on historical data, tool can predict impossible zone, may not be 100% accurate initially, but will be good start. And more data you provide to the tool, the more accurate predictions you will get.

Area of Impossible


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