Table 1 Dose-response/effect-based statistical analysis ( N =3)

French (2010) [8]

N: 28 studies

Analysis based on studies with multiple intervention components as follows:

The effectiveness of multifaceted interventions did not increase incrementally with the number of components

Interventions for Improving the Appropriate Use of Imaging in People with Musculoskeletal Conditions

Study designs: randomized controlled trials, controlled trials, interrupted time series

• 1 (N = 11)

• 2 (N = 7)

• 3 (N = 7)

• 4 (N = 1)

Populations: physicians, other

There was no relationship between the effect size and the number of intervention components as evidenced by

Settings: primary care practices, hospitals

• No statistical evidence of a relationship between the number of interventions used in the study group and the effect size (Kruskal-Wallis test, p = 0.48)

AMSTAR (quality) score: 9

• No statistical evidence of an increased effect size by increasing the number of components (quantile regression, coefficient -2.51, 95% CI: -11.58 to +6.56, p = 0.57)

Grimshaw (2004) [7]

N: 235 (283 papers)

Analysis based on studies with multiple intervention components as follows:

The effectiveness of multifaceted interventions did not increase incrementally with the number of components

Effectiveness and Efficiency of Guideline Dissemination and Implementation Strategies

208 studies were involved in this analysis

• 1 (N = 56)

Study designs: randomized controlled trials, controlled trials, controlled before-after, interrupted time series

• 2 (N = 63)

• 3 (N = 46)

• 4 (N = 28)

• 5 (N = 12)

Populations: physicians, nurses, pharmacists, other

• 6 (N = 2)

• 7 (N = 1)

Settings: primary care practices, hospitals, outpatient clinics, communities, nursing homes, other

There was no relationship between the effect size and the number of intervention components as evidenced by

AMSTAR (quality) score: 7

• For studies with no-intervention control groups, there was no statistical evidence of a relationship between the number of interventions used in the study group and the effect size (Kruskal-Wallis test, p = 0.18)

• There was no statistical evidence of a difference between studies that used multiple intervention control groups and studies with multiple intervention study groups (Kruskal-Wallis test, p = 0.69)

Shojania (2009) [26]

N: 32 studies

Analysis based on studies with 1 intervention component (N = 18 studies) and 1 or more intervention components (N = 14 studies)

Single interventions were more effective than multifaceted interventions

The Effects of On-Screen, Point of Care Computer Reminders on Processes and Outcomes of Care

Study designs: controlled clinical trials, randomized controlled trials

There was statistical evidence of a relationship between 1 and >1 interventions used in the study group and the effect size

Populations: physicians

• There was a significant difference in the effect size improvement between comparisons involving single (computer reminders alone) vs. usual care (no co-interventions) and multifaceted (computer reminders plus one or more co-interventions) vs. the other interventions alone (Kruskal-Wallis test, p = 0.04)

Settings: ambulatory care settings, hospitals, nursing homes, outpatient clinics, primary care practices

• The median improvement for single vs. usual care was 5.7% (IQR: 2.0% to 24.0%)

AMSTAR (quality) score: 8

• The median improvement for multifaceted interventions (that is computer reminders plus additional interventions versus those additional interventions alone) was 1.9% (IQR: 0.0% to 6.2%)