CODES= valid data codes |
Says what characters to recognize as valid codes in your data file, together with CODERANGE=. If XWIDE=1 (the standard), use one column/character per legitimate code. If XWIDE=2, use two columns/characters per valid code. Characters in your data not included in CODES= or CODERANGE= are given the MISSCORE= value. The highest category number 32767. CODES= can be up to 4,000 characters long. If CODES= and CODERANGE= are both specified, then the data are matched to CODES= first. CODES= can be rescored. CODERANGE= cannot be rescored.
Initially, Winsteps assumes that all items share the same response structure.
If there are 2 response codes in CODES=, then this is the Rasch dichotomous model
If there are 3 or more response codes in CODES=, then this the Andrich rating-scale model.
To override those,
If ISGROUPS=0, then this is the Masters partial-credit model. Each item is modeled to have its own rating-scale structure.
If ISGROUPS = AABBACDDCAADEEA, then the items are grouped to share rating scales.
The "A" group are items 1,2,5, 10,11,15 - they share the same rating scale.
The "B" group are items 3,4 - they share the same rating scale.
The "C" group ....
See also these Examples written with CODERANGE=
XWIDE=1 one character wide (the standard)
CODES=1234 four valid 1-character response codes
Example 2: There are four response choices. Each response takes up 2 columns in your data file and has leading 0's, so the codes are "01", "02", "03" and "04". Data look like: 0302040103020104040301
XWIDE=2 two characters wide
CODES=01020304 four valid 2-character response codes
Example 3: There are four response choices entered on the file with leading blanks, so that codes are " 1", " 2", " 3", and " 4". Data look like: 3 2 4 2 1 3 2
XWIDE=2 two characters wide
CODES=" 1 2 3 4" " required: blanks in 2-character responses
Note: when XWIDE=2 or more, both CODES= and the data value are left-aligned before matching, so both " 1" and "1 " in CODES= match both " 1" and "1 "in your data file.
Example 4: Your data is a mixture of both leading blanks and leading 0's in the code field, e.g. "01", " 1", " 2", "02" etc. The numerical value of a response is calculated, where possible, so that both "01" and " 1" are analyzed as 1.
XWIDE=2 two characters wide
CODES=" 1 2 3 401020304" two characters per response
Example 5: Your valid data are 1,2,3,4,5 and your missing data codes are 7,8,9 which you want reported separately on the distractor tables.
CODES = 12345789
NEWSCORE = 12345XXX ; missing values scored with non-numeric values
Example 6: The valid responses to an attitude survey are "a", "b", "c" and "d". These responses are to be recoded "1", "2", "3" and "4". Data look like: adbdabcd
CODES =abcd four valid response codes
NEWSCORE=1234 new values for codes
RESCORE=2 rescore all items
Typically, "abcd" data implies a multiple choice test. Then KEY1= is used to specify the correct response. But, in this example, "abcd" always mean "1234", so that the RESCORE= and NEWSCORE= options are easier to use.
Example 7: Five items of 1-character width, "abcd", then ten items of 2-character width "AA", "BB", "CC", "DD". These are preceded by person-id of 30 characters. Data look like:
George Washington Carver III dabcdBBAACCAADDBBCCDDBBAA
FORMAT=(30A1,5A1,10A2) Name 30 characters, 5 1-chars, 10 2-chars
XWIDE =2 all converted to 2 columns
CODES ="a b c d AABBCCDD" "a" becomes "a "
NEWSCORE="1 2 3 4 1 2 3 4 " response values
RES EDFILE= edit data file CORE=2 rescore all items
NAME1=1 name starts column 1 of reformatted record
ITEM1=31 items start in column 31
NI=15 15 items, all XWIDE=2
Example 8: Items are to rescored according to Type A and Type B. Other items to keep original scoring.
IREFER = AAAAAAAABBBBBBBBCCCCCCC ; 3 item types
CODES = 1234 Original codes in the data file
IVALUEA = 1223 Recode Type A items
IVALUEB = 1123 Recode Type B items
IVALUEC = 1234 Recode Type * item. Can be omitted
Example 9: The valid responses are percentages in the range 00 to 99.
XWIDE = 2 two columns each percent
; for data with leading zeroes,
CODES = 0001020304050607080910111213141516171819+
+2021222324252627282930313233343536373839+
+4041424344454647484950515253545556575859+
+6061626364656667686970717273747576777879+
+8081828384858687888990919293949596979899
or, for data with blanks,
CODES =" 0 1 2 3 4 5 6 7 8 910111213141516171819+
+2021222324252627282930313233343536373839+
+4041424344454647484950515253545556575859+
+6061626364656667686970717273747576777879+
+8081828384858687888990919293949596979899"
also recommended:
ISRANGE = *
1 0 99 ; defines the full range of the rating scale, regardless of the data
*
SFUNCTION=4 ; defines a smooth function for the Rasch-Andrich thresholds
Example 10: Codes are in the range 0-254.
XWIDE=3 ; 3 characters per response:
; for data with leading zeroes,
CODES="000001002003004005006007008009010011012013014015016017018019020021022023+
+024025026027028029030031032033034035036037038039040041042043044045046047+
+048049050051052053054055056057058059060061062063064065066067068069070071+
+072073074075076077078079080081082083084085086087088089090091092093094095+
+096097098099100101102103104105106107108109110111112113114115116117118119+
+120121122123124125126127128129130131132133134135136137138139140141142143+
+144145146147148149150151152153154155156157158159160161162163164165166167+
+168169170171172173174175176177178179180181182183184185186187188189190191+
+192193194195196197198199200201202203204205206207208209210211212213214215+
+216217218219220221222223224225226227228229230231232233234235236237238239+
+240241242243244245246247248249250251252253254"
;or for data with blanks
CODES=" 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23+
+ 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47+
+ 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71+
+ 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95+
+ 96 97 98 99100101102103104105106107108109110111112113114115116117118119+
+120121122123124125126127128129130131132133134135136137138139140141142143+
+144145146147148149150151152153154155156157158159160161162163164165166167+
+168169170171172173174175176177178179180181182183184185186187188189190191+
+192193194195196197198199200201202203204205206207208209210211212213214215+
+216217218219220221222223224225226227228229230231232233234235236237238239+
+240241242243244245246247248249250251252253254"
also recommended:
ISRANGE = *
1 0 254 ; defines the full range of the rating scale, regardless of the data
*
SFUNCTION=4 ; defines a smooth function for the Rasch-Andrich thresholds
Example 11: The data include negative values, -10, -9, through to positive codes 9, 10. Winsteps can only analyze data that are positive integers, so the data would need to be rescored:
XWIDE=3 ; each observation is 3 characters wide in the data file
; the next line is so that I can be sure that each code is 3 characters wide
; 123123123123123123123123123123123123123123123123123123123123123
CODES ="-10-9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 "
NEWSCORE="0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 "
also recommended:
ISRANGE = *
1 0 20 ; defines the ful range of the rating scale, regardless of the data
*
SFUNCTION=4 ; defines a smooth function for the Rasch-Andrich thresholds
Example 12: Codes in the range 0 - 1000.
; CODES= is impractical. Use CODERANGE= 0-1000
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