“…Interestingly, in many evaluation studies of psychological treatment of LBP inpatients, pain intensity is not included as an outcome measure (e.g. Fordyce, Fowler, Lehman, Delateur, Sand & Trieschmann, 1973;Newman, Seres, Yospe & Garlington, 1978 ;Swanson, Maruta, Swenson, 1979). Moreover, in in-patient studies, a behavioural operationalization of pain (e.g.…”