AP Physics 5 分标准参考

胡老师

AP Physics 1 scores 2015 -- more people passed Physics 1 than Physics B, and other commentary.

By now those of you who taught the inaugural year of AP Physics 1 have seen how their students did.  Not like the old physics B, eh?  Let's talk about the reasons for the ostensible precipitous decline in the scores.

Firstly, the raw score necessary to earn each AP grade has increased, by about 5-6% across the board.  Trinna Johnson and Trevor Packer sent a letter to the "AP Teacher Community" discussion group describing the score-setting process in tremendous detail.  In that letter, they revealed the grade cutoffs, which I've converted to percentage of available points necessary for each grade:

AP PHYSICS 1 GRADE          Percentage of available points on the test
     5                                                       71%
     4                                                       55%
     3                                                       41%
     2                                                       26%

The old physics B exam, typically, had cutoff scores of 65%-50%-35%-25%.  It takes more correct answers to pass now.

The AP Physics 1 exam, though, is considerably more difficult that Physics B.  There are no pity points available for simple calculations.  Synthesis is prized over recall.  There's no room to hide -- the questions probe for explanations rather than answers.  Due to the higher raw score cutoffs, we would expect fewer of our students to pass even on an exam of equivalent difficulty to AP Physics B. Now we have two effects that combine to reduce overall exam grades: a harder exam AND higher cutoff scores.

And finally, consider the population of students who took AP Physics 1 this year.

In 2014, 90,000 students worldwide took the AP Physics B exam; of these, 60% passed, and 14% earned 5s.  (That itself is a bit down from previous years, because the number of students taking AP B doubled over the previous decade.)  That works out to about 13,000 students earning 5s on Physics B, and 55,000 passing.

In 2015, 170,000 students took the AP Physics 1 exam -- just about double the population who previously took AP B.  Part of the intent of the redesign was to increase the pool of students who could handle an AP physics course.  Physics B was intended as a second-year course, and was so broad that it did not encourage serious, deep understanding.  Physics 1 is in fact for first-time advanced physics students.  Many schools appropriately replaced their "honors physics" courses with AP Physics 1.  Good.

But this twofold expansion in the student -- and teacher -- pool means a much broader range of student -- and teacher -- ability.  Many of the 80,000 additional students taking the exam were intrinsically weaker students.  And a bunch of teachers who were not experienced with college-level physics, or who were simply not yet capable of teaching college-level physics, were nevertheless thrown into an AP 1 course.  No wonder only 4% of the country earned 5s; no wonder only 37% passed.

Let's look at raw numbers now, not percentages.  On AP Physics 1, about 7,000 students earned 5s.  This is about half as many as earned 5s on Physics B.

But 63,000 students passed the AP Physics 1 exam -- that's considerably more than the 55,000 who passed AP Physics B  the previous year.  Even on a more difficult exam, even with higher standards for passing, more students passed this year than last.  Of course... because Physics 1 is intended as a first year course.  Sure, a bunch of folks tried this exam who weren't ready (or whose teachers weren't ready).  So what.  Thousands of folks who were ready just fine tried the new exam, and found out that they could do it.

As teachers forcibly learn that physics is about more than plugging numbers into equations, as students figure out that they can't write a bunch of baloney and expect to earn credit, AP Physics 1 scores should eventually improve.  It's on us to adjust our teaching to help these scores improve.

(from: Jacobs Physics)