Grading on a curve(Situation continued)
Originally, The Great Grading Scale formula was the average of four scales, each of which passes through (0,0) and (1,1) :
1) y = x, x is a %; for easy tests(mastery sought)
2) y = 1.442ln(x+1), x is %; for 1/4 hard & challenging tests
3) y = x^.5, x is a %; for 1/2 hard & challenging tests
4) y = x^(1/3), x is a %; for 2/3 hard & challenging tests
The average, TGGS, may be used for any challenging test:
y = { [x + 1.442ln(x+1) + sq rt(x) + cube rt(x)] / 4 }, x is a %.
Orange: Use TGGS for grading on a curve.
Build a table for the point value that you use mostly(send email for a spreadsheet template). I keep four scales handy: 15, 20, 24, & 100 points, corresponding to the total points on a given test. I keep item values small, 18(mostly 13) and demand that test items be at least 2/3 right just to earn 1/2 point. The great grading scale negates the need to give partial credit. This yields much better information about the content that needs to be reinforced. ...In the opening case, to reteach and test again may be the best option! By using TGGS, the fear of giving or taking hard and challenging tests may be greatly diminished.
