D. asked me about this term yesterday, and I had never heard of it before,
perhaps because I haven’t taught many courses where tests were involved.
As I now understand it (freshly, sketchily), washback describes
pedagogical revision, the on-the-fly adjustments teachers make after they have
evaluated a set of exams. The test, depending largely upon how well it is
designed, should report general strengths and weaknesses among the group;
washback is how the future lessons and activities are adapted in light of the
patterns indicated by the test.

I don’t know whether I will get much use out of the term, but it did get me
thinking about similar phenomena in writing courses. There is a kind of
going back over things–something like washback–that sometimes happens
depending on how a sequence of assignments is envisioned. It reminded me of a
mild tension in my MA program between those who thought a complete course of
study–including all writing assignments, prompts, and activities–ought to be
laid out from the outset and those who thought a course of study should be
designed to allow for those inevitable contingencies. To the extremes: the
first type is top-down, water-tight and risks being inflexible; the second type
is like taking to the air without a flight plan: improvisatory and roomy.
The first regards the contextual peculiarities (and surprises!) very little; the
second sets out with the proposition, "How can I devise the second unit of the
course until I know what happened with the first?". One values teaching
everything as if it is channeling toward week fifteen; the other lives and
teaches for today and wants not to overdetermine the what’s-to-come.

I am, at times, drawn to each of these extreme positions; they appeal to me
for different reasons. What I have come to understand is that, in moderate
forms, both are simultaneously possible, and good teachers understand–and
perform–them–a balancing act of managed flexibility. By now I have
wandered away from washback as it relates directly to tests and measurements,
but I only wanted to generalize it to the scenes of teaching I know best.