Example
From Fleiss (1993).
 
The data represent deaths after heart attack in seven different 
studies where the effect of giving aspirin was investigated.
 The data are provided in the test workbook in columns marked 
"Exposed total", "Exposed cases", "Non-exposed total", "Non-exposed cases" and "Study".
 
For this example:
Peto odds ratio meta-analysis
 
Stratum
Table (xt, xc, nt, nc)
 
1
49
67
566
557
MRC-1
2
44
64
714
707
CDP
3
102
126
730
724
MRC-2
4
32
38
285
271
GASP
5
85
52
725
354
PARIS
6
246
219
2021
2038
AMIS
7
1570
1720
7017
6880
ISIS-2
 
Stratum
O-E
Odds ratio
95% CI
Peto weight (V)
 
1
-8.578692
0.721713
0.492493
1.057619
26.304751
MRC-1
2
-9.540876
0.68386
0.462479
1.011214
25.107478
CDP
3
-10.780024
0.803583
0.607852
1.062341
49.29715
MRC-2
4
-3.447284
0.80134
0.487603
1.316943
15.565457
GASP
5
-6.258224
0.793516
0.544402
1.156621
27.058869
PARIS
6
12.986074
1.132558
0.934809
1.372138
104.323777
AMIS
7
-73.755746
0.895032
0.829531
0.965705
665.092282
ISIS-2
 
Stratum
z
P(two sided)
 
1
-1.672646
P = 0.0944
MRC-1
2
-1.904087
P = 0.0569
CDP
3
-1.535355
P = 0.1247
MRC-2
4
-0.873768
P = 0.3822
GASP
5
-1.203085
P = 0.2289
PARIS
6
1.271412
P = 0.2036
AMIS
7
-2.859927
P = 0.0042
ISIS-2
 
Pooled odds ratio = 0.896843 (95% CI = 0.840508 to 0.956954)
Z (test of odds ratio differs from 1)= -3.289276 P = 0.001
 
Non-combinability of studies
Cochran Q = 9.967823 (df = 6) P = 0.126
IČ (inconsistency) = 39.8% (95% CI = 0% to 73.3%)
 
Here we can say with 95% confidence that the true population odds of death for those who received aspirin after a heart attack from this set of studies is between 0.84 and 0.96 of the same odds for those not receiving aspirin.