I can't believe how long I have been teaching like this--giving big summative assessments without really knowing if they were ready or not.
When my students turn in a test or formal lab report and it becomes clear they haven't mastered major objectives, I have no one to blame but myself.
Had I known they were missing key pieces of the puzzle, I could have adjusted, re-taught, added more practice, or changed the summative assessment.
Instead, I didn't find out until it was too late.
Next time, Bill, gather more data before the big one.
After all, your job isn't to measure ability, but to increase it.