We have previously shown that these two instruments distinguished between patients who required admission to different levels of therapeutic security and distinguished the urgency of need amongst patients [ 11, 12].
We have shown that these scales have excellent psychometric properties and in a naturalistic cross-sectional study of patients in a forensic hospital, these instruments distinguished between those who are or are not allowed unaccompanied leave and between those who have progressed to pre-discharge units [ 4].
The reliability (median reliability coefficient 0.85 for all subscales) for the SF-36 has been established, 38– 40 and its validity has been shown in an elderly population, in which the instrument distinguished between those with and without poor health.
Moreover the instrument distinguishes between bulk impurities and surface contaminants.
The instrument distinguishes between cognitive, metacognitive and resource-related learning strategies and comprises dimensions of learning strategies grouped accordingly.
This analytical instrument distinguishes an abiotic, a biotic and an anthropogenic layer, which, integrated, shape the landscape.
The instrument distinguishes three styles: interventionist, non-interventionist and interactionist, and also covers three broad dimensions of classroom management - personality, teaching and discipline.
Although several quality of life instruments for paediatric asthma patients already exist, the Pelican instrument distinguishes itself because of its applicability in regular medical care.
Known groups validity refers to the extent to which scores on an instrument distinguish groups that differ on a key variable, usually clinical in nature.
The evaluation of treatment fidelity will use the Psychotherapy Process Q-Sort (PQS, [ 53, 54]) a 100 item instrument distinguishing key actions, behaviours and therapists' statements in different types of psychological therapy.
For example, differentiation between controlled observational studies, such as cohort studies, and observational studies without a control group, is possible, since the instrument distinguishes between factors affecting the necessity and feasibility of a control group, and those affecting the necessity and feasibility of randomisation and blinding.
