| Meranie psychoterapeutickej zmeny: porovnanie klasického testového skóre a skóre odvodeného prostredníctvom teórie odpovede na položku |
| Citlivosť na zmenu je dôležitou témou v hodnotení kvality meracích nástrojov na identifikáciu psychoterapeutickej zmeny. Štúdia sa snaží zamerať na problém, ako môže túto citlivosť ovplyvniť psychometrický prístup použitý pri hodnotení. Predmetom štúdie je porovnanie klasickej teórie testov (CTT) a teórie odpovede na položku (IRT) v ich citlivosti na zmenu. 166 osobám podstupujúcim psychoterapeutickú a psychiatrickú intervenciu bol administrovaný dotazník CORE-OM (Evans et al., 2000) pred a po intervencii. Na hodnotenie možnej zmeny boli vypočítané tak klasické skóre, ako aj IRT skóre. V oboch prípadoch bol použitý 95% konfidenčný interval štandardnej chyby merania na identifikáciu signifikantnej zmeny. Výsledky ukázali, že IRT prístup identifikoval viac osôb so signifikantnou zmenou než CTT. Ako sa ukázalo, dôvodom bola variabilita štandardnej chyby merania na špecifických úrovniach škály. |
| Klíčová slova: teória odpovede na položku,
meranie zmeny,
citlivosť voči zmene |
Peter Halama, Matúš Bieščad (2011). Meranie psychoterapeutickej zmeny: porovnanie klasického testového skóre a skóre odvodeného prostredníctvom teórie odpovede na položku. Československá psychologie, 55, 5, 400-411.
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| Measurement of psychotherapy change:
Comparison of classical test score and
IRT based score |
Objectives. The present study focuses on the
problem of sensitivity to change as an important
issue in evaluating the quality of measures
focusing on psychotherapy change. It deals with
the question on the problem how a psychometric
approach used in evaluation can influence
this sensitivity. The goal of the study is to compare
the two psychometric approaches: Classical
test theory (CTT) and Item response theory
(IRT), in their sensitivity to change.
Subjects and setting. The sample was 166 persons
undergoing psychotherapeutic and psychiatric
treatments as outpatients and inpatients.
Their symptom level was assessed by COREOM,
34-items long questionnaire based on selfrating.
It was made specifically for measurement
of psychotherapeutic change.
Statistical analysis. Both CTT and IRT scores
were computed as sources for assessing possible
change. For IRT score, Samajima graded
response model was used. In both cases, 95%
confidence interval of standard error of measurement
(SEM) was used to determine the statistically
significance of change.
Results. The results showed that IRT approach
identified more persons with statistically significant
change in comparison to CTT. As it was
found, higher sensitivity of IRT was due to variability
of SEM in IRT approach, which allows
more reliable measurement on specific levels of
trait scale. Also, difference in CTT and IRT was
found in the estimation of the trait levels, especially
at low level.
Study limitation. The generalization of the results
depends on item parameters of the considered
scales. Concept of clinical changes should
be taken into consideration, to analyze whether
statistically significant change identified by IRT
corresponds with actual changes in client’s functioning. |
| Keywords: IRT,
measurement of change,
sensitivity towards change |
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