Monday, 27 January 2014

Measuring Exploratory Testing

A quick post on a concept we are working on within our company

One of the difficulties I have found with implementing Exploratory Testing is a way to measure how much testing you have done at a high level (stakeholders).  This article looks at this problem and tries to provide a solution, it should be noted that there are good ways currently of reporting automation (checking) and for this article that will be out of scope.

The current way of we manage exploratory testing is by using time boxed sessions (session based test management) and for reporting at a project level we can (and do) use dashboards.  This leaves the question open of how much testing (exploratory) has been done against the possible amount of testing time available.

After having discussions with some work colleagues, we came up with the following concept (this was a great joint collaboration effort,I cannot claim the ideas as just mine).  The basic concept of session based test management is that you time box your exploration (charters) in to sessions where one session equates to one charter (if you have not come across the terminology of charters then refer to the session based test management link) To simplify we use an estimation that one session is half a day (sometime you do more, sometimes less), therefore we now have a crude way to estimate the possible number of charters you could run in a period of time.

For example if you have a sprint/iteration of two weeks you have per person a possible number of sessions you could run of 20 sessions, if you have 5 testers then you could have a total possible number of sessions of 5 * 20 = 100 sessions within your sprint.  No one on a project would be utilized like this for 100% of the time so the concept that we came up with is that for your project you set a target of how much of your time you want your team to be doing exploratory testing.  The suggestion is to begin with to set this to a value such as 25%, with the aim to increase this as your team moves more and more into automation for the checking and exploratory for the testing, the goal being a 50/50 split between checking and testing.

Using the example above we can now define a rough metric to see if we are meeting our target (limited by time)

If we have 2 weeks and 5 testers and a target of 25% exploratory we would expect by the end of the two weeks if we are meeting our target to have done: 25 exploratory sessions.

We can use this to report at a high level if we are meeting our targets within the concept of exploring, within a dashboard as shown below,

Possible sessions100
% Target Sessions25%
Number of actual sessions25
% Actual Target25%
Following this format we can this using colours to indicate if we are above or below our target: (red/green)

Possible sessions100
% Target Sessions25%
Number of actual sessions15
% Actual Target15%
We feel this would be a useful indication of the amount of time available and the amount of time actual spent doing exploratory testing rather than checking (manually or automated)

There are some caveats that go with using this type of measurement.

Within session based test management the tester reports roughly the amount of time they spend:
  • Testing
  • Reporting
  • Environment set-up
  • Data set-up
This is reported as a percentage of the total time in a session, therefore more detailed reporting can be done within a session but we feel this information would be of use at a project level rather than a stakeholder level.  This is something that, if it would be of use to stakeholders we could revisit and come back to.

Your thoughts on this concept would be most welcome and we see this as a starting point for a discussion that hopefully will provide a useful way at a high level to report how much time we are spent testing compared to checking.

We am not saying this will work for everyone but for us it is ideal way of saying to stakeholders that of all the possible time we could have spent testing (exploratory), this is the amount of time we did spend and the associated risks that may have.


  1. Nice, John. I see links to and

    Of course, you could measure testing done using other approaches as part of all this... and determine which approaches were finding bugs or revealing useful information.

    1. Thank yo for your comment Michael.

      I think your articles could have influenced me unconsciously whilst we were coming up with this concept. Thank you for adding the links so others can research further.

      PS - Regarding your approaches comment - we are using some tools, that should be able to show this very clearly.