Slide 1

RStats Statistics and Research Camp 2014

Meta-AnalysisSession 4

Melissa Maier, Ph.D.Assistant Professor

Communication

Slide 2

Rationale

• Narrative Review• Meta-Analysis:–Mathematical• Reduce Type II error• Correct statistical artifacts• Test possible moderator variables• Evaluate theoretical arguments

– Practical

Slide 3

Method

1. Construct database of all relevant research2. Analyze articles to determine (and correct):

1. Sample size2. Effect size3. Moderators

3. Calculate average effect size4. Test for homogeneity5. If heterogenous, test for moderators and

outliers

Slide 4

Calculate Ave. Effect

  Observed Effect (A)

Sample Size (B)

(A*B)

Study 1 .87 162 140.94Study 2 .86 151 129.86Study 3 .83 22 18.26Study 4 .77 121 93.17Study 5 .58 113 65.54Sum   569 447.77

d(ave) = ∑ (Observed effect * sample size) = 569 = 1.27∑(Sample Size) 447.77

Are female same-sex relationships more intimate than male same-sex relationships?

Slide 5

Test for homogeneity

d d – ave d (d – ave d)2 (d – ave d)2(N-k)

Study 1 .87 (.87 – 1.27) = -.40 .16 (.16) (162-5) = 25.12Study 2 .86 -.41 .17 24.82Study 3 .83 -.44 .19 3.23Study 4 .77 -.50 .25 29Study 5 .58 -.69 .48 52.84Sum 135.01

Testing for homogeneity

Χ2 = (d – ave d)2(N-k)

Slide 6

Write-up• Justification for review• Methodology

– Describe search methods– Code possible moderators (or model)– Describe statistical procedures

• Results– Average effect– Number of studies, k– Overall combined sample size, N– Measure of variability– Evaluation of homogeneity– Measure of significance of average effect

• Discussion

Slide 7

Limitations of Meta-Analysis

• Contextual restrictions• Unequal value of claims• Ethnographic trap• Multiplicity of interpretation• Misapplication of the level of

analysis

Slide 8

Supplemental ResourcesBurrell, N.A., Allen, M., Gayle, B.M., & Preiss, R.W. (Eds). (2014). Managing

interpersonal conflict: Advances through meta-analysis. New York: Routledge.

Hunter, J.E., & Schmidt, F.L. (1990). Methods of meta-analysis: Correcting error and bias in research findings. Newbury Park, CA: Sage.

Hunter, J.E., & Schmidt, F.L. (2002). Methods of meta-analysis: Correcting error and bias in research findings (2nd ed.). Thousand Oaks, CA: Sage.

Hunter, J.E., Schmidt, F.L., & Jackson, G.B. (1982). Meta-analysis: Cumulating research findings across studies. London: Sage.

Lipsey, M.W., & Wilson, D.B. (2001). Practical meta-analysis. Thousand Oaks, CA: Sage.

Preiss, R., & Allen, M. (1995). Understanding and using meta-analysis. Evaluation & the Health Professions, 18, 315-335.

Preiss, R., & Allen, M. (2001). Understanding and using meta-analysis. In R. Preiss, B. Gayle, N. Burrell, M. Allen, & J. Bryant (Eds.), Mass media effects research: Advances through meta-analysis (pp. 15-30). Mahwah, NJ: Lawrence Erlbaum.The Meta-Analysis Calculator:

http://www.lyonsmorris.com/ma1/