Friday 5 July 2013

The Assumption Bias and Testing: How Does It Influence You?

When testing a product, I aim to perform the kind of testing that will cover all of the areas that I believe are of value to the business. There have been times in my own testing where I have discovered only later in the piece additional areas to cover, areas that I had not originally thought to scope in due to assumptions of my own. Whilst I have been grateful to pick up on such things before the product ships, there always remained the risk that should there be a failure to do so, or should there be issues which arise around it later in the piece, this may impact the ability to deliver the product on time and to the expected specification.

Contrary to what some might assume, this is not a product of inexperience, but is instead a product of becoming so familiar with something you are testing, often based on extensive experience with testing similar things (and where the tester holds an extensive level of domain knowledge), that this increased level of confidence can impact our perspectives with the testing that we perform.

We can try and shape our perspectives by taking a focus on the bigger picture through asking questions, questions that guide the tester as to what knowledge about the product may offer the greatest value for the business. We can then use this information to help guide us with what areas to focus on when we are testing too.


This however still does not eliminate these assumptions we hold when performing this task. This is because it too remains an externally facing exercise, as we tend to not include ourselves as completely within the equation when performing such analysis.

The issues that stem from this are comparable to something that is labelled tacit knowledge. Tacit knowledge represents knowledge that is shared on a social level, but has not yet been documented so as to exist, at least on some level, in an explicit form.

Like tacit knowledge there exists an undocumented aspect, an aspect that can equally be influenced by the social, but in this case is much more centric to the individual. In these circumstances it relates to the absence of an evaluation of the biases and the assumptions that we bring to the table when performing test design and evaluating what we feel to be relevant test coverage.

If we take the time to first analyse and document these biases and assumptions before launching in and evaluating what testing we are looking to perform, we can use this knowledge to help shape our testing, so that what is and is not covered is no longer as influenced by such factors.

Such information gives us an opportunity to identify additional areas where test coverage might have otherwise been missed, and it becomes an additional source that we can utilise for future test planning too. In addition it serves as an opportunity to gain a greater awareness and understanding of these influences that we hold too.

Taking this very human element and being mindful of it and its influences, when creating test plans, can assist with giving us greater confidence that the testing we perform will be less likely to fall short due to such influences. This then helps us achieve the kind of coverage that can better assist with the delivery of a quality product.

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