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Fig. 2 | Systematic Reviews

Fig. 2

From: Many continuous variables should be analyzed using the relative scale: a case study of β2-agonists for preventing exercise-induced bronchoconstriction

Fig. 2

The effect of β2-agonists on exercise-induced bronchoconstriction in the IPD analysis. Each dot indicates one participant. The exercise-induced FEV1 decline after placebo is shown on the horizontal axis. The absolute effect of a β2-agonist is defined as the percentage point (pp) difference in the FEV1 declines after placebo and after β2-agonist, and is shown on the vertical axis, compare with Fig. 1. Lack of any effect of β2-agonist is indicated by the horizontal dashed line at the level of 0 pp., corresponding also to the relative effect of 0% (i.e. the FEV1 decline after β2-agonist is identical to the FEV1 decline after placebo treatment). Full removal of exercise-induced FEV1 decline is indicated by the upper diagonal dashed line corresponding to the relative effect of 100% (i.e. the FEV1 decline after placebo treatment is fully reversed after β2-agonist treatment). The mean absolute effect, defined by the intercept alone, is shown by the horizontal solid line at the level of 28 pp. The mean relative effect, defined by the slope alone, is shown by the diagonal solid line at the level of 90%. Abbreviations: pp., percentage points

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