However, ratios are difficult statistics to work with: in cost effectiveness ratios the denominator (the effect difference) may be zero, producing an intractable result.
22 23 Results of the bootstrap procedure were plotted in a cost-effectiveness plane that graphically represents the cost-difference and effect difference between either SDD or SOD and SC, and for SDD versus SOD, for each of the bootstrap replications.
No noticeable cytotoxic effect difference was detected between these two surfaces.
Among the tested materials, the effect difference of general combining ability of the β-carotene content was significant; however, the effect difference of the special combining ability and the reciprocal effect were not significant.
There was no evidence of significant effect difference between the uses of uFSH versus rFSH regarding any of the outcomes.
Afterwards, we have estimated the part of the effect difference between immigrants and natives that results from group attachment solely (immigrant fixed effect).
Identifying the part of the effect difference that cannot be explained by differences in sociodemographic composition is important for the targeting of programs to welfare recipients.
Since we are interested in the effect difference due to the attachment to the immigrant group, we call this residual part the immigrant fixed effect (IFE).
Although in some cases the multiplicative scale may naturally correspond to interaction mechanisms (Siemiatycki & Thomas 1981), the additive scale is of greater public health importance (VanderWeele 2011) because it allows researchers to discern the effect difference among subgroups.
Table 3 Treatment effect (difference between groups) in EQ5 score in 232 patients after LNG-IUS and hysterectomy after 1 and 5 years EQ5 dimensions Difference in EQ5 score Confidence interval Follow-up 1 year 0.0 −0.05–0.05 Follow-up 5 years 0.02 −0.02–0.029.
Thus, a reanalysis with the dichotomized CHRNA4 variable (C− vs. C+) revealed a more stable Load x Genotype interaction, F 1, 400) = 5.9, P = 0.016, η2 = 0.03, with a significant simple effect difference in the high load condition, t(200) = 2.2, P = 0.027, but not the low load condition, P = 0.29 (see figure 5B).
