“…Only a few studies are so far available that have produced equivocal results concerning predictors of a successful outcome of pain-oriented procedures such as relaxation training for LBP (Freeman, Calsijn, Paige & Halar, 1980;Keefe, Block, Williams & Surwit, 1981;Keefe, Schapira, Brown, Williams & Surwit, 1981). In order to place the therapeutic improvement achieved in this study in a proper perspective, it is illuminating to compare patient characteristics of this study with those reported in other controlled treatment studies of LBP (Engstrom, 1983;Flor, Haag, Turk & Koehler, 1983;Linton & Gotestam, 1984;Linton & Melin, 1983;McCauley et a/., 1983;Nouwen & Solinger, 1979;Turner, 1982). Taking into account the limited information on patient characteristics in most studies, the population of LBP patients in this study seems somewhat older, has a relatively long history of back pain, consists of a relatively large number of patients who have undergone back operations and includes hardly any patients who are employed.…”