[LON-CAPA-users] Action items page

Gerd Kortemeyer lon-capa-users@mail.lon-capa.org
Wed, 21 Sep 2005 08:47:33 -0400

Hi Lars,

On Sep 21, 2005, at 2:12 AM, Lars Jensen wrote:

> (2)Once, I checked off the "Reset Count" box, that seemed to remove  
> the problem for a while, but it popped back into the list later? Why?

Because the criterion set still applies, even after another batch of  
students went through.

> (3) Problems seem to pile up in a long list... Is there no other  
> way to shorten the list than checking off each problem  
> individually, and resetting the counter? It seems like a "check  
> all" button on this page might be a good idea.

Yep, same here initially. The default criteria for the warnings are  
set to be pretty sensitive. There is a button in the heading of that  
column where you can adjust the warning levels. I have set them to  
degree of difficulty greater than 0.8, at least 5 tries, and at least  
three students meeting the criterion before issuing the warning. Now  
it's useful for a 220 student course. I think the default criteria  
were designed to also match smaller courses, but I am afraid we were  
overly cautious.

Remaining bug: essay problems still always issue warnings.

> (4) What is the "degree of difficulty" of a problem?

I don't remember the formula, but it involves number of tries till  
students succeed. Works pretty well:

0: everybody gets it (probably a broken problem, always right on the  
first try)
< 0.3: easy problem
0.3<x<0.7: good problem
 > 0.7: hard problem
1: nobody ever gets it (probably broken problem)

I analyzed the quality of ensuing online student discussions as a  
function of degree of difficulty and actually got significant  
results. At least when it comes to students discussing concepts with  
each other (rather than expressing frustration, etc), anything beyond  
0.7 only increases the pain, not the gain.

- Gerd.