Design
A psychometric study was conducted, translating the QPC-FIPS instrument into Spanish and assessing its psychometric properties, including content validity, convergent validity, construct validity, internal consistency, and test-retest reliability.
Phase 1
Adaptation of the Quality Psychiatric Care - Forensic Inpatient Staff (QPC-FIPS) instrument. This phase was carried out following the recommendations of experts in questionnaire adaptation.
Phase 2
Validation of the psychometric properties of the QPC_FIPS-Spanish scale. This phase consists of a psychometric study of the reliability and validity of the Spanish version of the QPC_FIPS instrument in a sample of professionals in forensic mental health units.
Study sample
The sample consisted of professionals from different disciplines who work in forensic mental health units (nursing, psychiatry, psychology, social education, nursing assistance, social work, and occupational therapy), who participate voluntarily. Having less than six month’s experience in the area of mental health was established as an exclusion criterion. Non-probability convenience sampling was used.
Calculation of the sample size was based on internal consistency and temporal stability. Estimation of internal consistency was performed following the recommendations of Streiner, Norman & Cairney, who considered that between 5 and 20 individuals should be included for each instrument item 22. To analyze temporal stability, it was estimated that a minimum of 60 professionals would be needed to detect an intraclass correlation coefficient (ICC) around 0.70 between two administrations of the instrument, assuming a confidence level of 95% and a power of 80% in a bilateral comparison 23.
Variables, instruments and sources of information
First, the sociodemographic and labor data of the sample were collected: age, sex, professional category, time of experience in the unit.
Professional perception of quality care was obtained using QPC-FIPS-Spanish. This version is an adaptation of original questionnaire QPC-FIPS21.
The QPC-FIPS is a self-administered questionnaire consisting of 34 items and measures 7 dimensions of quality of care: encounter (8 items), participation (8 items), discharge (3 items), support (4 items), isolation (2 items), safe environment (3 items) and forensic specifications (6 items). Each item is related to the statement "I consider that..." and responses are based on 4-point Likert scales, where 1 corresponds to "strongly disagree" and 4 to "strongly agree". All items also have the option "does not correspond".
To analyze convergent validity, the NTP 394 general satisfaction scale created by Warr et al. 24 was used. This scale, which evaluates working conditions (intrinsic and extrinsic), consists of 15 items evaluated on a scale of 1 to 7 (1 “very dissatisfied” and 7 “very satisfied”). The version used for the convergent validity was the one validated in Spanish by Pérez and Fidalgo 25.
Procedure and data collection process
The translation and back-translation process was carried out following the Standards for Educational and Psychological Testing 26.
First, the original version was translated into Spanish by two independent native-speaker translators who had no knowledge of the instrument or the aims of the study. A group of experts comprising a specialist in psychometrics, three quality experts, five nurses specializing in mental health, a psychologist and a psychiatrist specializing in forensic medicine previously assessed semantic equivalence (grammatical difficulties in translation, equivalent meaning of words), and idiomatic (contextualization of the text, colloquialisms) and conceptual equivalence. The translation and back-translation process did not present any major difficulties. The expert committee suggested modifying only two items. Item 30 ("staff help patients, if they wish, to present their wishes and their case to the administrative court" for "users can access the judge through their lawyer or the legal guidance service") and item 33 ("patients receive help from the staff to elaborate their crime" for "during the stay in the penitentiary the professionals help the users to talk about the crime they committed"). Finally, the term "patients" was replaced by "users" and "staff" by "professionals", and inclusive non-discriminatory language was used when referring to gender.
Finally, a pilot cognitive pretest, was carried out on 30 professionals in order to assess comprehension and completion time. The average time taken to complete the questionnaire ranged between 15 and 20 minutes and no item presented difficulty regarding comprehension. Following the debriefing, it was not considered necessary to make any changes to either format of content. The Spanish adapted version of the QPC-FIPS scale was configured by the same number of items and dimensions as the original, with the final version in Spanish named QPC_FIPS-Spain.
The adaptation and psychometric evaluation process was carried out in four forensic mental health units at Parc Sanitari Sant Joan de Déu, Barcelona, Spain. Data collection was carried out between February, 2019 and December, 2021.
Statistical analysis
The SPSS Statistics program version 26 was used for analyses, along with EQS program version 6.2 for the confirmatory factor analysis (CFA) 27.
Construct validity
Construct validity was analyzed through confirmatory factor analysis (CFA) with estimated parameters using the method of least squares generalized with a polychoric correlation matrix. The criteria for a good fit were BBNFI, BBNNFI, GFI, AGFI, CFI close to 0.90 28–30; the ratio of chi square to degrees of freedom (χ2/df) < 3. The value of the mean square approximation error (RMSEA) and the standard error of standardized root mean (RMSR) was less than 0.08 31,32
Convergent validity
The General Satisfaction Scale NTP 394 was used for convergent validity; an analysis of the Pearson correlation coefficient was performed. Furthermore, as an additional method, a Pearson correlation analysis was also performed between the factors of the QPC-FIPS questionnaire with the aim of verifying the Fayers & Machin 33 hypothesis which indicates that the correlation was higher between each factor and the general scale than the correlations between the subscales.
Reliability
To evaluate the internal consistency of the instrument at a general level and for each of the factors, Cronbach's alpha was used, with a value greater than or equal to .70 22 considered adequate reliability. Temporal stability or test-retest reliability was evaluated after 7–14 days through the CHF in a sample of 77 professionals. A value greater than or equal to .70 was considered an indicator of good agreement 22. In addition, composite reliability was calculated. Item analyses included the calculation of item means, standard deviations, and corrected total item correlation.
Ethical aspects of research
This study was approved by the research ethics committee at the Sant Joan de Déu Foundation, under CEIC code PIC-73-18. All research was conducted in accordance with relevant guidelines and regulations. All participants were informed about the objective of the study and gave their written consent to participate voluntarily and anonymously.