The aim of this technique is to make underlying assumptions
more visible.
- Identify a particular choice you have made, and ask yourself
why you feel it is the best choice – i.e. what assumptions
guide this choice.
- List the assumptions, and beside each write a counter-assumption
- not necessarily its negation, but the opposite to the issue it
represents.
- Work down the list and delete ineffective assumption/counter-assumption
pairs i.e. where it would make little difference to your choice
whether the assumption or the counter-assumption were actually the
case.
- Assess each of the remaining assumptions in terms of high or low
potential impact (how critical is its truth to justifying your pattern
of behaviour?) and high or low plausibility (how confident are you
that it is, in fact, true?).
- Plot the assumptions on a 2x2 matrix (high/low impact on one axis,
high/low plausibility on the other).
| |
Plausibility |
Low |
High |
Potential
impact |
High |
medium |
Most serious |
| Low |
Least serious |
medium |
High impact/high plausibility assumptions are clearly
the most crucial, but high impact/low plausibility assumptions need
to be taken seriously, in case they turn out to be true, so check them
out if you can.
The assumptions in the ‘high impact’ cells
are those that the user sees as largely justifying their actions. Are
they over-estimating them? What could change these assumptions? What
benefits would there be and for whom?
The assumptions in the ‘low impact’ cells
are seen as less critical, but it might be worth checking this out –
are they being under-estimated?
[source:
www.mycoted.com]