Messages

1

Questions and Answers / Re: Characteristic Curves by Category

« on: March 23, 2015, 07:13:27 PM »

Hi!
Thanks for worrying, but I sort of solved it in another way.
Thanks again!

2

Questions and Answers / Re: Characteristic Curves by Category

« on: January 07, 2015, 10:55:56 AM »

Thank you!

3

Questions and Answers / Re: Characteristic Curves by Category

« on: December 15, 2014, 12:13:13 PM »

Hi all,

I have still the problem that Conquest says "Item thresholds are not available for models without discrete and increasing scores, within item multidimensional models, models with non-integer scores, or models with null categories".

And there is another thing I am wondering about: If I use the Rasch model with the key statement and compare it to the results I get from using the ordered partition model (see syntax above) I get different item difficulties. Why is that?

4

Questions and Answers / Re: Characteristic Curves by Category

« on: November 24, 2014, 10:31:51 AM »

I plotted Characteristic Curves by Category (ICC).

May the model statement be the problem?

5

Questions and Answers / Re: Characteristic Curves by Category

« on: November 21, 2014, 12:17:27 PM »

Thanks again for the quick answer!

This is what my syntax looks like:

set constraints=cases;
datafile data_distr.dat;

format responses 9-31;

labels << labels_dist.lab;

score (1,2,3,4) (1,0,0,0) !item (16);
score (1,2,3,4) (0,1,0,0) !items (3,4,5,10,11,13,18,20,22);
score (1,2,3,4) (0,0,1,0) !items (1,2,6,12,14,19,23);
score (1,2,3,4) (0,0,0,1) !items (7,8,9,15,17,21);

codes 1,2,3,4;
model item;
estimate;

When conquest stops calculating, it says "Item thresholds are not available for models without discrete and increasing scores, within item multidimensional models, models with non-integer scores, or models with null categories".

When I look at the characteristic curves by category, I get a "smoothed" line for the correct response and only one "smoothed" line for the incorrect responses. But what I want is a "smoothed" line for every category.

What am I doing wrong?

6

Questions and Answers / Re: Characteristic Curves by Category

« on: November 20, 2014, 02:09:33 PM »

Hi Eveline,

thanks a lot for your quick answer. I used the key-statement for the model (the items have 4 answer options 1, 2, 3, 4 and there is always one correct answer). The key statement in my syntax then indicates which answer is correct.
If there is no other possibility than using the ordered partition model, could somebody post the lines I would have to exchange?

Thanks!

7

Questions and Answers / Characteristic Curves by Category

« on: November 19, 2014, 10:39:27 AM »

Hi everyone!

I am working with MC-items and I want to analyse the characteristic curves "by category" to understand my items better. Plotting those curves, concquest (or poltquest) uses the raw data for the curves representing the probability for the distractors. Is there any possibility to get "smoothed" model porbability curves for all categories? Right now, conquest just shows this model probability curve for the right answer.

Thanks for you help!

Maria