For the eight items measuring SQOL in the DIALOG intervention, the study identified a satisfactory internal consistency, a very high convergent validity with scores on the MANSA, and a meaningful factorial structure. One factor captured mental and physical health as well as personal safety, whilst the other factor comprised satisfaction with all social areas of life. The lowest loading of any item was for satisfaction with job situation, which is a particular domain in this patient group since most patients are without regular employment. For the three treatment satisfaction items, the internal consistency was substantially lower and the convergence with the CSQ scores was moderate. For both SQOL and treatment satisfaction scores, the correlations with symptom levels were plausible and in the expected direction and range [27
]. Longitudinal data were obtained within the intervention arm of a randomised controlled trial in which DIALOG was repeatedly used. Over a period of up to a year, SQOL and treatment satisfaction scores showed significant improvements indicating that they are sensitive to change.
The study did not assess the construct validity of the SQOL and treatment satisfaction scores in DIALOG. The face validity may be regarded as high which is essential for the intervention: only if the patients and clinicians regard the items as important and relevant, are they likely to use the intervention routinely and regularly for structuring their communication.
A recent review of PROs in patients with psychosis has suggested that the validity of scales with satisfaction items is based on more evidence than assessment methods using other types of questions [28
]. All 11 items used in the DIALOG intervention are satisfaction ratings and therefore may be seen as using the best evaluated approach for assessing PROs in this patient group.
To what extent do the findings of this study justify the use of the scores that are generated in the DIALOG intervention, i.e. in a meeting with a clinician that has a therapeutic purpose, as psychometrically acceptable outcome data? The eight SQOL items appear to provide a valid measure of SQOL. The items are identical with items used in the MANSA, and the analysis in this study shows that the reduction of 12 SQOL items in the MANSA to eight in the DIALOG intervention does not compromise the psychometric properties.
For treatment satisfaction, the findings are less clear. Three is the minimum number of items constituting a scale and, by definition, the internal consistency of scales decreases with fewer items. Also, for the therapeutic purpose of the DIALOG intervention, the items are designed to cover distinct areas of treatment, which further compromises the internal consistency of a three-item scale. In light of this, the internal consistency found in this paper may be seen as reasonable and sufficient for using the score in the evaluation of outcomes. The correlation with CSQ is moderate which may be explained by the different focus of the two scales. Whilst CSQ covers community health care in a more general sense, the three items in DIALOG address the main components of treatment that is provided in community mental health teams, i.e practical help, talks with mental health professionals and medication. Although the three items cover different treatment aspects, their mean score is sensitive to change, which is important for monitoring treatment outcomes.
The findings suggest that the SQOL and treatment satisfaction scores generated in the DIALOG intervention possess sufficient psychometric properties to be used as outcome data in the evaluation of routine community mental 'health care. Using the data of a regularly administered therapeutic intervention as outcome evaluation may be a solution to the problem of generating PROs in routine care. The obvious advantage is that neither clinicians nor patients would have to engage in a separate exercise for assessing such outcomes making the procedure most economical. Possibly even more important is that the approach overcomes the common problem of low response rates and selection biases in patient surveys. In the study, all patients who consented to participate in the trial and were allocated to the intervention generated PROs within DIALOG. Using the data of the DIALOG intervention means that outcome data is available for every single patient who participates in the intervention, which is equivalent to a response rate of 100%. The existing research evidence [12
] suggests that the intervention can be used with a wide range of patients, including those with severe and persisting psychotic disorders. Thus, the approach is likely to provide PROs data with much less selection bias than separate surveys and other separate outcome assessments.
Integrating outcome assessments in clinical routine meetings raises the issue as to whether PROs should be assessed in a meeting with the clinician rather than with an independent researcher or administrator. If patients rate their satisfaction for life and treatment in the presence of their clinicians, the rating may be biased, e.g. in the direction of social desirability. However, experimental research has shown that such a bias neither consistently nor substantially influences PRO ratings in this context [29
]. Moreover, if the ratings are to be used to evaluate and improve the quality of individual treatment, clinicians must be aware of them regardless; therefore, the potential rating bias can never be totally avoided.
Assessing outcome data in the DIALOG intervention is consistent with the principles for implementing routine outcome assessment in mental health services as identified in a review by Slade [9
]. He concluded that standardised measures should be used, that data collection should be cheap and simple, that feedback should quick, easy and meaningful and that data should be collected longitudinally. He further emphasised the importance of minimising the time of clinicians spent on this, and of the role of technology in preserving it. DIALOG complies with all of these recommendations, and is free to use and easy to implement. It is mainly a therapeutic intervention to make the communication between patient and clinician more effective.