Different situations inspire testing teams to adopt different size metrics for work. In a post at his blog, Tom Cagley touches upon the factors that should influence how you approach test measurements. Here are three considerations:
- How testing is organized
- Where testing is incorporated into the value delivery chain
- Whether work is being done for a fee
Molded to the Situation
When it comes to organization, there are typically two models seen—one where there are independent test groups, and another where testers are part of the team. In the former case, independent testers are going to size work for themselves, separate from developer work. As such, metrics that count things like test cases and test case points are likely to be emphasized. By comparison, with teams with embedded testers, their metrics will end up just aligning with that of the rest of development.
Next is observation of the value chain. The more integrated into development that testing is, the more likely testing will be to use size metrics that really fixate on functional deliverables, as opposed to arbitrary counts of items. And about work for fee, Cagley writes this:
Outsourced testing is an extreme version of the independent test group. Outsourced test groups that price by project face all of the same issues as teams doing any outsourced piece of work. With the exception of open, time and material contracts, the testing team needs some basis for the estimate that allows them to complete the work and make a healthy profit margin. Just like many development groups that have begun to leverage cost per function point, testing providers are experimenting with cost per test case point.
For further elaboration, you can view the original post here: https://tcagley.wordpress.com/2017/04/13/deciding-which-size-metric-works-for-testing/