Alfa Cronbacha – co daje dobre wyniki? Kilka uwag dotyczących budowania kwestionariuszy psychologicznych

Tomasz Rak

Uniwersytet Papieski Jana Pawła II w Krakowie
https://orcid.org/0000-0002-3522-5176

Szymon Wrześniowski

Uniwersytet Papieski Jana Pawła II w Krakowie
https://orcid.org/0000-0001-5553-4016


Abstrakt

Cokolwiek mierzy alfa Cronbacha – nie jest to spójność wewnętrzna, powszechnie błędnie rozumiana w psychologii jako średnia siła związków pomiędzy pozycjami kwestionariusza. W tym artykule badamy powody, dla których rozumienie alfa jako spójności wewnętrznej jest błędne i skupiamy się na działaniu inflacji (przeszacowania) współczynnika alfa w praktyce. Na bazie symulacji komputerowych określiliśmy dokładny (wspólny) wpływ na wartość alfa: liczby respondentów, zakresu skal pomiarowych (Likerta), liczby pytań w kwestionariuszu (itemów) oraz średniej korelacji między pozycjami. Wyniki potwierdzają występowanie inflacji poziomu alfa ze względu na liczbę pytań: alfa osiąga zadowalające wartości nawet przy minimalnej spójności wewnętrznej, jeśli w kwestionariuszu jest dużo itemów. Sugerujemy, że w przypadku słabych narzędzi pomiarowych rzetelność może być przeszacowywana ze względu na prezentowany tu krzywolinowy wzrost alfa. Liczba osób badanych i zakres skali nie miały wpływu na wartość alfa.


Słowa kluczowe:

rzetelność, alfa Cronbacha, inflacja alfa, spójność wewnętrzna, symulacje


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2023-12-31

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Rak, T., & Wrześniowski, S. (2023). Alfa Cronbacha – co daje dobre wyniki? Kilka uwag dotyczących budowania kwestionariuszy psychologicznych. Przegląd Psychologiczny, 66(4), 67–84. https://doi.org/10.31648/przegldpsychologiczny.10084

Tomasz Rak 
Uniwersytet Papieski Jana Pawła II w Krakowie
https://orcid.org/0000-0002-3522-5176
Szymon Wrześniowski 
Uniwersytet Papieski Jana Pawła II w Krakowie
https://orcid.org/0000-0001-5553-4016