1. Galina Larina 28-31 of March, 2012 University of Ostrava
ConQuest: preparation of data, work with the program, the interpretation of output data
Galina Larina
28-31 of March, 2012
University of Ostrava

2. About this program Advantages Disadvantages
Generalized Item Response Modeling Software
ConQuest developed by Australian Council for Educational Research (ACER) and University of California, Berkeley
Advantages
Disadvantages
Works with a big number of models, including Many-Facet and Multidimensional ones (Rasch)
Reports a confidence interval for fit statistics
Good item analysis
Creates a variable map
Many outputs
Requires making of control file
Requires special knowledge on interpretation outputs in complex analysis
Doesn’t work with 1PL and 2PL models and their polytomous extensions

3. Application Performing item analysis Exploring rater effects
Examining DIF
Estimating latent correlation and testing dimensionality
Fitting a wide variety of item response models:
Rasch’s Model
Rating Scale Model
Partial Credit Model
Multifaceted Models
Multidimensional Item Response Models
etc.

4. Performing item analysis (Rasch analysis) .shw
These tables are for the term item (dichotomous items) and term item*step (polytomous items), as the first and second terms in the model statement

5. Performing traditional item analysis .itn
This table shows summary results
These outputs conclude tables showing classical difficulty, discrimination and point-biserial statistics for each items (dichotomous and polytomous)

6. Performing item analysis Map of latent distributions .shw
There are two maps in ouputs:
- response model parameter estimates
- generalized-items tresholds
This histogram illustrates the distribution of student’s achievement. In this example each ‘X’ means 9.7 cases.
Items are plotted to indicate their difficulty level
These are Thurstonian thresholdes for each of the items. The notation x.y is used to indicate the y-th thresholds of the x-th item.

7. ConQuest Plots Dichotomous item

8. ConQuest Plots Polytomous item

9. ConQuest Examinees
ID number Raw score that Maximum Student’s latent Standard error
student attained possible score ability

10. Steps of work Data No missings, recode ones
Only numerical or letter symbols in matrix data
Individual file with matrix data
Without unique ID
Or with unique ID (in columns 1 through 9)
Save your data in Notepad and name it like ex1data.dat

11. Steps of work Variable labels
Individual file with variable labels looks like
First line of the file is required
===> item
Amount of spaces doesn’t matter
In this example the label for item 1 is BSMMA01, the label for item 2 is BSMMA02, and so on.
Save your data in Notepad and name it like ex1names.dat

12. Steps of work Command File
Example
Save your command file in notepad and name it like ex1run.dat

13. ConQuest Commands
Datafile indicates the name and location of the data file
Format statement describes the layout of the data in the file ex1data.dat. In this example id 1-9 means unique id is located in columns 1 through 9. And responses means that the responses to the items are in columns 10 through 26
Labels indicates the name and location of the file with variable labels
Export logfile indicates the name and location of the logfile
Codes identifies all valid codes in data file

14. ConQuest Commands
Key statement identifies the correct response for each of multiple-choice item.
Dichotomous test:
Key ! 1;
Non-dichotomous test:
Key ! 1;
Key xxxx22xxxxxx2xx2 ! 2;
Model specifies the item response model that is to be used in the estimation.
model item in case of simple logistic model. We are dealing with single-faceted dichotomous data
model item + item*step in case of PCM. We are dealing with polytomous items or a mixture of dichotomous and polytomous data
model item + step in case of RSM. We are dealing with polytomous items, where the step parameters are the same for all items
And so on…

15. ConQuest Commands
Estimate statement initiates the estimation of the item response model. You can select some special options for your analysis:
type of method
maximum number if iterations
etc.
Show statement produces a sequence of tables that summarizes the result of fitting the item response model. The result are redirected to a file ex1.shw in this example.
Show cases statement produces a display of the results of a examinee analysis. The result are redirected to a file ex1_stud.shw in this example. You can select the type of estimate - it can be eap, latent, mle or wle.
Itanal statement produces a display of the results of a traditional item analysis. The result are redirected to a file ex1.ita in this example.

16. ConQuest Run the program
File – Open –
Find your command file
2. Run – Run all

17. ConQuest Manual Manual consist of four sections:
Introduction provides a brief survey of the models that ConQuest can fit
Tutorial contains nine samples of ConQuest analysis and describes how to use the program to address particular problems without any underlying methodology
Technical Matters provides underlying in ConQuest methodology
Command Reference contains general information about the syntax of ConQuest statements

18. Exploring rater effects Raters .shw
Fit statistics for the raters. These ones lap over it’s confident interval.

19. Exploring rater effects Criteria .shw
Fit statistics for the criteria. These ones lap over it’s confident interval.

20. Exploring rater effects Maps of the parameter estimates.shw
Examinee Rater Criteria
Examinee Rater.Criteria.Step

21. Exploring rater effects Plots

22. Testing dimensionality

23. Multidimensional model Control file

24. Multidimensional model .shw Correlations/covariance between dimensions
COVARIANCE/CORRELATION MATRIX
Dimension
Dimension
Dim
Dim
Variance
Covariance coefficients
Correlations coefficients

25. Multidimensional model .shw Reliability coefficients
Between-Item
RELIABILITY COEFFICIENTS
Dimension: (Dim 1)
MLE Person separation RELIABILITY: Unavailable
WLE Person separation RELIABILITY: Unavailable
EAP/PV RELIABILITY:
Dimension: (Dim 2)
EAP/PV RELIABILITY:
лалала

26. Multidimensional model .shw Examinees