A Method for Estimations: Adjusted Use Case Points

Although there are several methods for estimations, when you don’t have a detailed functional analysis as a starting point, the more suitable one is Adjusted Use Case Points.

This method has basically two inputs (use cases to be developed, and productivity of the team) and two sets of adjustment variables (Technical and Environment). The key point for this method is to find out which your team productivity is. The best way to do this is to start with a market standard value and then, as you test it in actual projects, find the productivity that most suits you.

Below are the flow and the steps to prepare an estimation:

Fig-01

Actors & Complexity:

In this section, you have to identify a different kind of users and interfaces for the application. Human actors using screens, usually users and administrators, always are considered as complex, batch interfaces when you read or write a file as a mean to interchange data are consider as simple, and finally, interfaces with devices or real-time connections with applications are considered average.
 Fig-02

Use Cases & Complexity:

Now, based on application functional requirements, you have to identify all the use cases/features and for each one of them determine its complexity.

Fig-03

Weighting:

Based on actors and use cases definition, the method automatically applies standard weights and calculates the unadjusted use case points.

Fig-04

Adjustments:

The next step to perform is to set the adjustment variables.

Technical Complexity Factor (TCF)

Here is an example of the set of technical variables taken into account for the method. For each one of them, you have to evaluate and set a value from zero to five which best represents your technical requirements.

Fig-05

This is the first adjustment factor.

Environment Factor (EF):

Next, there are the environment variables taken into account for the method. As with technical variables, for each one of them you have to evaluate and set a value from zero to five which best represents your environment situation.

Fig-06

This is the second adjustment factor.

Now, using the adjustments factor explained above, the method calculates the adjusted use case points:

Fig-07

Effort Estimation

Introducing the productivity in hours corresponding to each adjusted case point, the method transforms the adjusted case points into hours. The standard value used for productivity is 20 hours per adjusted use case point; nevertheless, each team has to find the most suitable value to obtain accurate estimations.

Given the knowledge of our products and industry at Intraway, we started using the method, applying a productivity of 18 hours per adjusted use case point.

Fig-08

This estimation includes all the activities involved in a project. Using the industry standard percentage distribution for activities, the result is:

Effort Distribution

Fig-09

Finally, we can filter the activities corresponding to Engineering and obtain the development estimation.

As we said before, at Intraway we are now starting to use this method in parallel with estimations by experts, in order to find the better value for our productivity measure.

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