Bond & Fox (2001) Applying the Rasch Model ...

Chapter 7: Pendulum Interview

You will need to read the text of the book to understand these examples. Official authors' website: Bond & Fox
Winsteps numerical results may differ somewhat from those in Bond & Fox due to differences in estimation procedures.

B&F Pendulum Interview data p. 97

The entire dataset is obtained from www.jcu.edu.au/~edtgb.

The original data set contains 18 items and 58 children.

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Title = "B&F PCM Analysis of Piagetian Interview Data: 18 items"
Item1 = 3        ; Response to first item is in column 5
NI    = 18       ; 18 items used.
Name1 = 1        ; Person identifier starts in column 1
Xwide = 1        ; Each observation is 1 columns wide
Codes = 0123     ; valid codes 0-3.
clfile=*         ; label the rating scale categories
0 Not            ; deduced from Table 7.2
1 Action
2 Logic
3 Correct
*
Groups= 0        ; each item is in its own group ("Partial Credit" model)
Total = Yes      ; show total raw scores
Chart = Yes      ; produce across-pathway picture
Mnsq  = No       ; use Standardized fit statistics
Uimean= 0        ; Item mean difficulty at 0.
Stbias= Yes      ; Adjust for estimation bias
&End
1  Order lengths ; deduced from Table 7.2
2  Order weights
3  Order push
4  Length-freq
5  Vary factors
6  Infer
7  Tests lengths
8  Tests weights
9  Tests push
10 Length role
11 Weight role
12 Push role
13 Length combine
14 Weight combine
15 Push combine
16 Systematic
17 Exclude weight
18 Exclude push
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Start Ministep.
Do not answer the "Control File Name?" question.
Go immediately to "Edit" pull-down menu.
Click on "Edit/Create File with WordPad"
WordPad screen opens.
"Paste Special" as "Unformatted Text" what you just copied above.

It should look exactly like the block above.

"Save as"
Go to the C:\WINSTEPS directory
File Name: PCM.txt
Save as type: Text document
"Save"
"You are about to save the document in a Text-Only format ..."
Click "Yes"

Click on Ministep or Winsteps on the bottom of your screen
"Control File Name?" displays.
Press the Enter key
Find PCM.txt in the file list.
Click on it.
Click "Open"

"Report output file name ..."
Press the Enter key

"Extra specifications ..."
Press the Enter key

Ministep runs.
Ministep reports "Measures constructed"

B&F Figure 7.1 paralled p. 99

You know what to do ...
Table 13.2 for the general view of the pathway
Table 2.0 for the thresholds, scroll down to Table 2.3 (50% Cumulative Probability.)

B&F Table 7.3 p. 101

Table 14 for the items in entry order for dichotomous item difficulties and item fit statistics.
Table 3.2, Rating scale structure, for the partial credit item thresholds, look at the second panel, "50% Cumulative Probility". Their standard error is approximately the error column.

Winsteps Table 13:
+--------------------------------------------------------------------------------------+
|ENTRY   TOTAL                  MODEL|   INFIT  |  OUTFIT  |PTMEA|                     |
|NUMBER  SCORE  COUNT  MEASURE  S.E. |MNSQ  ZSTD|MNSQ  ZSTD|CORR.| ITEM              G |
|------------------------------------+----------+----------+-----+---------------------|
|     2     56     58   -2.48     .71|1.10    .4|1.16    .5|  .05| 2  Order weights  0 |

B&F Table 7.3
      2                 -2.36     .73         .3         .5 

B&F Table 7.3
      6.1               -2.41    1.25         .0        -.2
Corresponds to Winsteps 3.2
      6 1               -2.58    1.04 1.02        .94
        
FOR GROUPING "0" ITEM NUMBER: 6  6  Infer
+--------------------------------------------------------------------------
|CATEGORY    STRUCTURE   |  SCORE-TO-MEASURE   | 50% CUM.| COHERENCE|ESTIM|
| LABEL    MEASURE  S.E. | AT CAT. ----ZONE----|PROBABLTY| M->C C->M|DISCR|
|------------------------+---------------------+---------+----------+-----+
|   0      NONE          |( -3.67) -INF   -2.67|         |   0%   0%|     | 0 Not
|   1       -2.53   1.04 |  -1.10  -2.67    .46|   -2.58 |  50%  27%| 1.02| 1 Action
|   2         .32    .30 |(  1.46)   .46  +INF |     .38 |  72%  89%| 1.02| 2 Logic
+--------------------------------------------------------------------------

Winsteps reports mean-squares (expected values = 1.0) for categories instead of t-statistics for thresholds.
+------------------------------------------------------------------
|CATEGORY   OBSERVED|OBSVD SAMPLE|INFIT OUTFIT||STRUCTURE|CATEGORY|
|LABEL SCORE COUNT %|AVRGE EXPECT|  MNSQ  MNSQ||CALIBRATN| MEASURE|
|-------------------+------------+------------++---------+--------+
|  0   0       1   2|  -.15  -.03|   .93   .78||  NONE   |( -3.67)| 0 Not
|  1   1      18  31|   .74   .74|  1.02   .94||   -1.42 |  -1.10 | 1 Action
|  2   2      39  67|  1.47  1.47|   .98   .99||    1.42 |(  1.46)| 2 Logic
+------------------------------------------------------------------

B&F Figure 7.2 p. 102

Table 12. Scroll down to 12.6. This pictures the 50% Cumulative Probability Thresholds

Note: The Winsteps instructions on p. 104-105 are conceptual.

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