Personas, substruction and other trades’ tricks

Developing personas is a well-described technique (see Alan Cooper’s ‘The Inmates are Running the Asylum’ and Mike Cohn’s ‘User Stories Applied’) for considering the different kinds of users of the system we are developing. On a recent project, we began considering the different users who might want to user our product. In the process, I was able to connect it to another recently acquired trick and gain further insight into the user of our system.

The initial features added to our system seemed to be really only considering one type of user. Most of the team felt strongly that there were other important users who were being ignored, as many of the features didn’t seem to work the way we expected them to. They made sense for the targetted user, but made little sense when we thought about how *we* would want to use the system.

This suggested to us two user types – The bargain hunter and the traveller. We imagined the traveller to be someone planning a future trip. They were looking for discounted goods or services that would be available for them to use on holiday, some time in the not-immediate future. We also imagined a bargain hunter, someone for discounted goods and services, with a sense of urgency. This is the kind of shopper who hates to miss out on a bargain. Our system forced us to consider this kind of user as the primary customer.

It seemed that the two had some common objectives, but different needs. We tried to model this –

This begged the question –

What about these customers? Who might they be? We wondered if we could give them a name, and if they were worth considering?

We named them. They were important customer types whose needs had to be taken into account.

The Special Occasioner – A person who is looking for a good deal, but is prepared to take time to find it. Perhaps for a wedding anniversary, or someone who is planning a holiday, but hasn’t firmly decided.
The Last minuter – A person who leaves things to the last minute, has to unexpectedly travel, or just acts on the spur of the moment.

It was at this point that I flashed back to my recent reading of Howard Becker’s ‘Tricks of the trade‘, and his writing on ‘Substruction’. He describes substruction as –

‘…the logical converse of reduction. Reduction puts combinations together for the sake of simplicity. Substruction takes them apart, in the interest of discovery.’

As it turns out, this is exactly what we had just been doing. From analysis of our initial two personas, we were able to derive two more, and on further analysis we expanded this even further.

Here’s the process –

1. Determine the important attributes of a persona. In our case, we started with two, but you may have more.
2. Write down all the combinations of presence and absence of the attributes. This may be a truth table, but Becker’s book provides examples for non-binary attributes.
3. Work out which combinations of present or absent attributes correspond to the personas you have already thought of.
4. See which combinations don’t have a name. Try to name them.

Personas are a great tool. Enhancing the approach with the techniques of substruction gave us a much richer model of our system and the kinds of people who may have an interest in using it, and points to possibilities we may not have considered. Howard Becker’s book, though targetted at sociologists, is a great read for anyone looking to improve their thinking.