Prevention of Alcohol Purchase and Use Among Prevention of Alcohol Purchase and Use Among

AdolescentsAdolescents Design TwoDesign Two::

Staggered Entry of 10 Staggered Entry of 10 Intervention SitesIntervention Sites

Harold D. Holder, Ph.D.Harold D. Holder, Ph.D.Senior Scientist, Prevention Research Center,Senior Scientist, Prevention Research Center,Pacific Institute for Research and EvaluationPacific Institute for Research and Evaluation

Berkeley, CA Berkeley, CA

Prevention of Alcohol Purchase and Use Among Prevention of Alcohol Purchase and Use Among

AdolescentsAdolescents Design TwoDesign Two::

Staggered Entry of 10 Staggered Entry of 10 Intervention SitesIntervention Sites

Harold D. Holder, Ph.D.Harold D. Holder, Ph.D.Senior Scientist, Prevention Research Center,Senior Scientist, Prevention Research Center,Pacific Institute for Research and EvaluationPacific Institute for Research and Evaluation

Berkeley, CA Berkeley, CA

National Institutes of HealthNational Institutes of Health May 4-5, 2004May 4-5, 2004

Design 2--RationaleDesign 2--Rationale

(3) Reaction bias- Communities which are (3) Reaction bias- Communities which are denied intervention can create their own denied intervention can create their own intervention which confounds ability to be intervention which confounds ability to be controls.controls.

(3) Reaction bias- Communities which are (3) Reaction bias- Communities which are denied intervention can create their own denied intervention can create their own intervention which confounds ability to be intervention which confounds ability to be controls.controls.

(1) Documentation- Requirement of NIH reviewers(1) Documentation- Requirement of NIH reviewersto have signed agreements of participationto have signed agreements of participation

creates local awareness and expectation.creates local awareness and expectation.

(1) Documentation- Requirement of NIH reviewers(1) Documentation- Requirement of NIH reviewersto have signed agreements of participationto have signed agreements of participation

creates local awareness and expectation.creates local awareness and expectation.

(2) Ethics- (2) Ethics- Systematic denial of intervention, Systematic denial of intervention, based upon selection criteria.based upon selection criteria.

(2) Ethics- (2) Ethics- Systematic denial of intervention, Systematic denial of intervention, based upon selection criteria.based upon selection criteria.

Design 2: OutlineDesign 2: Outline

3.3.

4.4.

1.1.

2.2.

10 communities with 5 selected for 10 communities with 5 selected for first wave of interventionfirst wave of intervention

Communities not included in first Communities not included in first wave have delayed initiation, e.g., in wave have delayed initiation, e.g., in pairspairs

Selection for initiation waves can be random Selection for initiation waves can be random or purposeful.or purposeful.

Requires parallel outcome measurementRequires parallel outcome measurement

Essential to know dates of actual Essential to know dates of actual implementation and dosage/strength of implementation and dosage/strength of implementation in all communities.implementation in all communities.

5.5.

Enables test of sufficiency of intervention (short term compared to longer term)

6.

Design twoDesign two

T1 T2 T3 T4 T5 . … . . .. . . TnT1 T2 T3 T4 T5 . … . . .. . . Tn

OO11 X O X O22 O O33 O O44 O O55 ……….O ……….Onn

OO1 1 OO2 2 X O X O33 O O4 4 O O55

OO11 O O2 2 OO33 X O X O4 4 O O55

OO11 O O22 O O33 O O4 4 XX OO55 . . . .. . . .. . . . . . . .

Trade OffsTrade OffsRCTRCT Design 1Design 1 Design 2Design 2

AssignmentAssignment (Permits (Permits effectiveness trial but requires effectiveness trial but requires large candidate pool)large candidate pool)

Permits trial with fewer Permits trial with fewer cases and enables cases and enables communities to develop communities to develop interventions which match interventions which match their values and norms.their values and norms.

Permits trial with fewer cases Permits trial with fewer cases and enables communities to and enables communities to develop interventions which develop interventions which match their values and match their values and norms.norms.

Controls Controls (can be biased (can be biased with mismatched trends)with mismatched trends)

Can control for trending Can control for trending using matchingusing matching

May be difficult to obtain May be difficult to obtain matching controls for matching controls for trendingtrending

EthicsEthics (denial of (denial of intervention, moderate risk of intervention, moderate risk of contamination)contamination)

Denial of intervention, Denial of intervention, moderate risk for moderate risk for contamination but less than contamination but less than Design 2Design 2

No denial of intervention but No denial of intervention but increased risk of increased risk of contamination.contamination.

AttributionAttribution (IF (IF randomization fulfilled and randomization fulfilled and no contamination, then easier no contamination, then easier to attribute effects)to attribute effects)

Requires greater complex Requires greater complex analyses to increase analyses to increase confidence in attribution of confidence in attribution of effect.effect.

Requires greater complex Requires greater complex analyses to increase analyses to increase confidence in attribution of confidence in attribution of effect.effect.