Tuesday, 15 September 2015

Testing skills - Abductive Reasoning

This is the first in a series of hopefully short articles which looks at  skills and techniques outside the traditional testing that can be useful to those who practice testing.

Future topics planned include:

  • Influencing by listening
  • Note Taking
  • Leading teams
  • Persuasion and how to sell
  • Speaking the language of business 
  • Remote teaching experiential style
  • Going beyond the model
If you can think of any others that would be useful please leave a comment. 

I am making these public,  since by writing it down and making it public I am committing myself to do it.  That is your first tip in this article, if you want to commit to doing something which you keep putting off, writing it down and make it public.

Abductive Reasoning.

 Abduction came about from the work of Jo Reichert, in this work Reichertz came up with another cognitive logic process to describe discovery when the researcher encountered surprising findings in the data. He called this "a cognitive logic of discovery".  Before this there were two types of reasoning in common use, 'inductive' and 'deductive'.
  • Inductive - Making generalized conclusions from specific observations
  • Deductive - Proving or disproving a theory from observations (scientific method)
Abductive reasoning is an important process for those involved in testing.  The majority of time when we are testing we discover surprising behavior in the software.  This normally makes us rethink our theories of how the software works and as such we begin to re-evaluate our understanding of the software.  We create a new rule, or test idea to further investigate the surprising element of what we have just tested. This is key within grounded theory; our thoughts about the software and how it behaves change as we explore the software more.  How we report these surprises and the behavior of the software is crucial to the value that testers provide to a project.
"There are two strategies involved in abduction, both of which require creating the conditions in order for abductive reasoning to take place"* (Reichertz, 2007: 221). 
The first is a ‘self-induced emergency  situation’ (Reichertz, 2007: 221). This means that in the face of not knowing what to make of a surprising finding, rather than dwelling on the infinite number of  possibilities, the analyst puts pressure on themselves to act by committing to a single meaning.
The second strategy is completely antithetical to the first. It involves letting your mind wander without any specific goal in mind, or what Pierce (1931–1935), a key writer on abduction, called ‘musement’* (Reichertz, 2007: 221). "
Qualitative Research Methods in Psychology: From core to combined approaches - Nollaig Frost - 2011.
Reichertz makes the following observation about these two strategies.
"What these two quite antithetical strategies have in common is tricking the thinking patterns of the conscious mind in order to create ‘an attitude of preparedness to abandon old convictions and to seek new ones."
 The SAGE Handbook of Grounded Theory:(Sage Handbooks) - Antony Bryant, Kathy Charmaz  - 2010.
Testers need to be able to abandon their old convictions and seek out new ones.  This is especially important when we are testing software, since our biases and beliefs and previous experiences can influence our decision making. Using some of the methods described in this book can allow us to challenge our thinking about the software and engage in abductive reasoning.

One famous use of abductive reasoning is that used by the fictional detective Sherlock Holmes by Sir Arthur Conan Doyle.  Many people believe, wrongly, that Sherlock Holmes uses deductive reasoning to solve his cases, when in reality he used abductive reasoning.
"Holmes' method doesn't resemble deductive reasoning at all. Instead, it's much more similar to a form of reasoning known as "Abductive Reasoning"Debunking Sherlock Holmes Myths - Maiza Strange  May 2014
To summarise abductive reasoning is taking your best guess based upon your current knowledge, observations and experiments.  These pieces of information maybe incomplete but you use your cognitive reasoning processes to form a theory or conclusion.  For example:
"A medical diagnosis is an application of abductive reasoning: given this set of symptoms, what is the diagnosis that would best explain most of them? Likewise, when jurors hear evidence in a criminal case, they must consider whether the prosecution or the defense has the best explanation to cover all the points of evidence. While there may be no certainty about their verdict, since there may exist additional evidence that was not admitted in the case, they make their best guess based on what they know."Deductive, Inductive and Abductive Reasoning - Butte College.
This article has been taken from the Testing and the Social Science chapter in my book - The psychology of Software #Testing.


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