Cross-cultural adaptation and validation of the Spanish version of the Cardiopulmonary Resuscitation Motivation Scale (s-CPRMS): a cross sectional study

Initially, the s-CPRMS consisted of 43 items, as in the original version. Content validity was analyzed by a panel expert (N = 13) who evaluated the content of the items in terms of relevance for measuring motivation in CPR. The expert panel consisted of a multidisciplinary team of researchers with experience in developing and validating instruments in health sciences, as well as educators with PhDs and professionals in critical care, emergency, and pre-hospital care in the Spanish health context. The CVI for the entire scale (s-CVI) and for each item (i-CVI) was calculated using a Likert scale of 1 to 4. (1 = not relevant at all, 2 = not very relevant, 3 = quite relevant, and 4 = very relevant). The researchers agreed on a minimum score for s-CVI > 0.80, as well as, the inclusion of items with i-CVI ≥ 0.78. The i-CVI was calculated by summing the scores of experts who considered the item quite relevant or very relevant divided by the total number of experts [33]. Item wording was also evaluated in terms of understanding and clarity, with the possibility of suggesting improvements through comments to ensure the suitability of the instrument to the Spanish context. Experts reported adequate equivalence, readability, and understanding without the need to add new items to the final version of the s-CPRMS, which consisted of a total of 24 items.

In this study, the construct validity of the s-CPRMS was tested by performing an exploratory factor analysis (EFA) and confirmatory factor analysis (CFA).

An EFA was computed using the principal axis factoring method with oblimin rotation to examine construct validity. In this study, data were not normally distributed and a polychoric matrix was used for EFA as the most suitable when all the variables are Likert scale [34]. The appropriateness of the data for EFA was assessed by the Kaiser–Meyer–Olkin (KMO) and Bartlett’s test of sphericity (BTS), considering appropriate to conduct an EFA when KMO > 0.70 and the BTS was significant (p < 0.05). The number of the factors to be extracted was determined using scree plot with parallel analysis and eigenvalues ≥ 1. A minimum factor loading ≥ 0.3 was set to retain the items in the extracted factors.

A CFA was computed to verify the latent structure of s-CPRMS and the model fit proposed by EFA. The goodness of fit indexes used for model assessment included χ2, Standardized Root Mean Square Residual (SRMR) ≤ 0.08 indicating good fit, Root Mean Square Error Approximation (RMSEA) ≤ 0.05 indicating a well-fitting model, Tucker–Lewis Index (TLI), Comparative Fit Index (CFI) and Goodness-of-Fit Index (GFI) whit values ≥ 0.95 indicating excellent fit [35].

A pilot study was conducted with physicians and nurses (N = 50) working in critical care and emergency care services to analyze the reliability of the instrument, internal consistency and temporal stability. Cronbach’s alpha values could underestimate the results of ordinal measurement scales [36, 37]; therefore, ordinal alpha was calculated to estimate the internal consistency of the response scale of ordinal items, considering acceptable and excellent values > 0.7 and > 0.9, respectively [38]. The mean inter-item correlation was calculated, with values between 0.2 and 0.4 suggesting that the items are reasonably homogeneous [39]. A good corrected item-total correlation (C-ITC) was considered when values were > 0.3 [40]. Inter-item correlations were also evaluated, and coefficients between 0.15 and 0.5 were considered acceptable [41].