A Checklist Beats Being Clever
Last timeWho Would Bother
Ask the same six questions at every boundary on the drawing. The output is a list with a known shape, which is worth more than whatever the most imaginative person in the room thought of.
Why a checklist
The instinct at this point is to get the right people in a room and think
hard. That produces findings and it produces the wrong ones.
A brainstorm surfaces what the room is already worried about. The person
who spent last quarter on authentication raises authentication. The
engineer who was on call during the outage raises availability. Those are
real concerns and they were already known, which means the meeting
produced no new information at considerable expense.
The difference is coverage you can state. After a brainstorm you know what
you found. After a checklist you know what you looked for, and the second
is the only thing that supports a claim that the system was examined.
| findings the team alread | findings new to everyone | coverage that can be sta | hours it took | |
|---|---|---|---|---|
| an afternoon of discussi | 3 | 1 | 0 | 2 |
| the same people with a c | 1 | 3 | 3 | 1 |
There is a secondary benefit that matters in a real team. A checklist is
dull, and dullness is a feature, because it means the quality of the
output does not depend on who was feeling imaginative that afternoon. The
same pass run by two different groups produces broadly the same list.
The six questions
Six categories cover the attacks on a boundary. They are not a theory,
they are a list that has survived being used, and their only virtue is
that between them they ask about every way a message crossing a line can
go wrong.
The lesson stops here
3 more paragraphs to go
You have read the opening. The rest of the argument, the problems that check whether it landed, and the lines worth keeping at the end all come with a plan.
The first lesson of every course in the library reads the whole way through, free, so you can see exactly what the rest of them are.
See the planThe contentsThis is the reading half
Starting the course gives you your own copy of it. Every idea on every page has problems standing under it, marked with a reason rather than a tick, and any sentence you do not believe can be opened and argued with. None of that can happen on a page nobody owns.
The contents