Hi all,
I am doing a research on functional disability and I have read some papers that used Item Response Theory model (IRT) to create disability scores instead of using binary or continuous variables. Here is a quote "Basically, IRT is used to develop a calibrated disability score (the dependent variable) which is derived using a partial credit model with item calibration. An item calibration is obtained for each item. To determine how well each item contributed to common global health measurement, chi-square fit statistics are calculated. The calibration for each of the health items is taken into account, and the raw scores are transformed through Rasch modeling into a continuous cardinal scale (0, worst health; 100, best health)".
In fact, I have read instructions on how to construct disability scores using IRT from some papers but it seems still confused to me and I do now know how to start. I am posting an example of a data set so that ones may take a look and I hope that someone is familiar with these techniques and can give me a right direction.
Thank you.
Best regards,
DL
I am doing a research on functional disability and I have read some papers that used Item Response Theory model (IRT) to create disability scores instead of using binary or continuous variables. Here is a quote "Basically, IRT is used to develop a calibrated disability score (the dependent variable) which is derived using a partial credit model with item calibration. An item calibration is obtained for each item. To determine how well each item contributed to common global health measurement, chi-square fit statistics are calculated. The calibration for each of the health items is taken into account, and the raw scores are transformed through Rasch modeling into a continuous cardinal scale (0, worst health; 100, best health)".
In fact, I have read instructions on how to construct disability scores using IRT from some papers but it seems still confused to me and I do now know how to start. I am posting an example of a data set so that ones may take a look and I hope that someone is familiar with these techniques and can give me a right direction.
Code:
* Example generated by -dataex-. To install: ssc install dataex clear input byte(i9a1 i9a2 i9b1 i9b2 i9c1 i9c2 i9d1 i9d2 i9e1 i9e2 i9f1 i9f2 i9g1 i9g2 i10a1 i10a2 i10b1 i10b2 i10c1 i10c2 i10d1 i10d2 i10e1 i10e2) 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 1 1 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 1 3 1 3 1 4 1 2 1 4 1 3 1 2 1 2 1 3 1 4 1 4 1 2 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 1 1 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 1 2 2 . 1 2 1 2 2 . 2 . 2 . 2 . 2 . 2 . 1 2 1 3 1 4 2 . 1 1 1 1 2 . 2 . 2 . 2 . 2 . 2 . 2 . 1 2 1 1 1 1 2 . 1 1 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 1 1 2 . 1 2 1 1 1 1 2 . 2 . 2 . 2 . 2 . 1 4 1 2 1 4 2 . 1 2 1 2 2 . 1 3 2 . 1 3 1 2 1 3 2 . 2 . 1 3 1 1 1 2 2 . 2 . 2 . 2 . 2 . 2 . 2 . 1 3 1 3 1 2 2 . 1 3 1 1 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . 2 . end label values i9a1 LABEL_I9A1 label def LABEL_I9A1 1 "Yes", modify label def LABEL_I9A1 2 "No", modify label values i9a2 LABEL_I9A2 label def LABEL_I9A2 1 "Mild", modify label def LABEL_I9A2 2 "Moderate", modify label def LABEL_I9A2 3 "Severe", modify label def LABEL_I9A2 4 "Can not do at all", modify label values i9b1 LABEL_I9B1 label def LABEL_I9B1 1 "Yes", modify label def LABEL_I9B1 2 "No", modify label values i9b2 LABEL_I9B2 label def LABEL_I9B2 2 "Moderate", modify label def LABEL_I9B2 3 "Severe", modify label values i9c1 LABEL_I9C1 label def LABEL_I9C1 1 "Yes", modify label def LABEL_I9C1 2 "No", modify label values i9c2 LABEL_I9C2 label def LABEL_I9C2 1 "Mild", modify label def LABEL_I9C2 2 "Moderate", modify label def LABEL_I9C2 3 "Severe", modify label def LABEL_I9C2 4 "Can not do at all", modify label values i9d1 LABEL_I9D1 label def LABEL_I9D1 1 "Yes", modify label def LABEL_I9D1 2 "No", modify label values i9d2 LABEL_I9D2 label def LABEL_I9D2 1 "Mild", modify label def LABEL_I9D2 2 "Moderate", modify label values i9e1 LABEL_I9E1 label def LABEL_I9E1 1 "Yes", modify label def LABEL_I9E1 2 "No", modify label values i9e2 LABEL_I9E2 label def LABEL_I9E2 1 "Mild", modify label def LABEL_I9E2 2 "Moderate", modify label def LABEL_I9E2 3 "Severe", modify label def LABEL_I9E2 4 "Can not do at all", modify label values i9f1 LABEL_I9F1 label def LABEL_I9F1 1 "Yes", modify label def LABEL_I9F1 2 "No", modify label values i9f2 LABEL_I9F2 label def LABEL_I9F2 1 "Mild", modify label def LABEL_I9F2 2 "Moderate", modify label def LABEL_I9F2 3 "Severe", modify label values i9g1 LABEL_I9G1 label def LABEL_I9G1 1 "Yes", modify label def LABEL_I9G1 2 "No", modify label values i9g2 LABEL_I9G2 label def LABEL_I9G2 1 "Mild", modify label def LABEL_I9G2 2 "Moderate", modify label values i10a1 LABEL_I10A1 label def LABEL_I10A1 1 "Yes", modify label def LABEL_I10A1 2 "No", modify label values i10a2 LABEL_I10A2 label def LABEL_I10A2 2 "Moderate", modify label def LABEL_I10A2 3 "Severe", modify label values i10b1 LABEL_I10B1 label def LABEL_I10B1 1 "Yes", modify label def LABEL_I10B1 2 "No", modify label values i10b2 LABEL_I10B2 label def LABEL_I10B2 3 "Severe", modify label values i10c1 LABEL_I10C1 label def LABEL_I10C1 1 "Yes", modify label def LABEL_I10C1 2 "No", modify label values i10c2 LABEL_I10C2 label def LABEL_I10C2 3 "Severe", modify label def LABEL_I10C2 4 "Can not do at all", modify label values i10d1 LABEL_I10D1 label def LABEL_I10D1 1 "Yes", modify label def LABEL_I10D1 2 "No", modify label values i10d2 LABEL_I10C3 label def LABEL_I10C3 2 "Moderate", modify label def LABEL_I10C3 4 "Can not do at all", modify label values i10e1 LABEL_I10E1 label def LABEL_I10E1 1 "Yes", modify label def LABEL_I10E1 2 "No", modify label values i10e2 LABEL_I10C4 label def LABEL_I10C4 2 "Moderate", modify label def LABEL_I10C4 3 "Severe", modify
Best regards,
DL
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