Trust in Nurses Scale: construct validity and internal reliability evaluation.

Aim: This paper is a report of the continued psychometric evaluation of the Trust in Nurses Scale.

Background: Qualitative analyses indicate that trust in nurses is critically important to adult patients. Instruments that distinctively measure this concept are lacking. A middle-range theory of patient-centred nursing care provided the theoretical basis for the Trust in Nurses Scale. Content validity was assessed by an expert panel and patient interviews. Construct validity and reliability were found acceptable using multi-trait/multi-item analysis techniques. These findings were previously reported.

Methods: Construct validity and reliability of the Trust in Nurses Scale was assessed in 2007 using data collected during 2004-2005 from 187 hospitalized patients in a haematology-oncology setting. Trust in nurses (the latent factor) was operationalized by five items (manifest variables) using confirmatory factor analyses. Fit statistics included comparative fit index, Tucker-Lewis Index, root mean square error of approximation and the standardized root mean square residual. Internal consistency reliability was assessed using coefficient alpha.

Findings: Both a five-item and a four-item version demonstrate acceptable psychometric properties. The five-item version met three fit statistics criteria. Fifty-nine per cent of the variance was explained. A four-item version met all fit statistics criteria. Sixty-six per cent of the variance was explained. Acceptable internal consistency reliability was found for both versions.

Conclusion: Previous psychometric testing of the Trust in Nurses Scale provided evidence of the instrument's reliability, content validity and construct validity. The presented analyses further support construct validity. Thus, cumulative findings indicate that the instrument measures with a few items the underlying concept of trust.