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method, this point is said to be reached with scores that fall outside the range of the dysfunctional behaviour, where the range is described as being two standard deviations in the direction of improvement. In the second method, the cut-off point is reached when scores fall within the functional range where the range is set at two standard deviations above (in the case of the measurement of dependence) the measurement for the normal population. The third method proposes a cut-off point where scores indicating the level of functioning suggest the client is statistically more likely to be in the functional than the dysfunctional population.
Table 9.5 Total dependence scores at intake (t1) and three months (t2), and the difference between these scores for those in Sample 6c who achieved a reliable change in their dependence score at t2; n = 50
LDQ t11
mean 20.5
SD 6.6
median 21
mode 21*
LDQ t22
6.7 6.2 5
0
LDQ ch3 t1 - t2
13.7 6.2 12
8
1 total dependence score at intake
2 total dependence score at three months
3 difference between total dependence scores at t1 and t2 calculated as t1-t2. * smallest of a number of modes
At three month follow-up, 50% of the follow-up Sample 6c had a reliable change score greater than 1.96, which, based upon Jacobson and Truax (1991), is likely to reflect real change, that is, a measure of change not attributable to the unreliability of the measurement instrument. Dependence data at t1 and t2 for the 50% (n = 50) of Sample 6c (n = 101 but dependence data were missing for three participants) who fulfilled the criterion for reliable change at t2 are presented in Table 9.5.
Of the 50 individuals who had a reliable change score >1.96 for dependence at t2, 31 had reduced their dependence score to 9 or below, that is within two standard deviations above the general population mean (Raistrick et al. 1994). This calculation is based upon the second of the three methods proposed by Jacobson et al. (1999) which can be applied for the purpose of meeting the second of the criteria for asserting that clinically significant change has occurred. While the mean dependence score for this group was reduced from 18.2 at t1 to 2.8 at t2, showing a mean change of 15.3 points, it increased between t2 and t3 to a mean score of 9.3 showing a mean change
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