The questionnaire has not been subjected to validity or reliability testing in this study, although similar items for cognitive social capital have been employed in past studies [22], [23].
This is also complicated by the heterogenicity of existing simulators being subjected to validity testing [ 66].
The SF-36 scale to determine quality of life was subjected to validity and reliability testing for its use in Turkish.
Second, the selection of participants for this study may have been subject to issues with external validity, as we restricted our population to nighttime patients.
The structured interview instrument used to collect information about PO characteristics and capabilities has not been subjected to rigorous validity testing, which may have introduced unintended "noise" into our data.
Also, efforts to incorporate the synthetic estimates of unhealthy behaviour developed by the National Centre for Social Research (Bajekal et al., 2004) which have been subjected to various validity assessments (Pickering et al., 2004), should be explored, which may allow for inclusion of synthetic estimates of binge drinking within the unhealthy lifestyle index.
While the absolute values of cost of care estimates are subject to the validity and reliability of currently available data, dynamic systems modeling allows for future trends to be estimated.
The final form of the CRU scale (post-iteration 3), presented in Additional File 1, was subject to further validity assessments of: content (sample 2, expert panel assessment) and internal structure and relations to other variables (sample 3, pilot test).
Importantly, both instruments have been subjected to reliability and validity evaluation.
Instead, scales are composed of items that have been subjected to tests of validity to show that they can serve as reasonable proxies for the underlying construct they represent (DeVellis, 2003).
