Table 1

Characteristics of Studies Reporting on School Absences.*

Study
Intervention Group
Control Group
Duration (Months)
Standardized Effect Size**

N
Mean ± SD
Rate
N
Mean ± SD
Rate



Charlton
42
2.10 ± 11.40
0.18
37
4.70 ± 15.50
0.39
12
-0.19
Christiansen
27
2.39 ± 2.90
0.20
15
2.98 ± 3.29
0.25
12
-0.19
Colland
45
0.98 ± 1.56
0.16
34
0.53 ± 1.08
0.09
6
0.32
Dahl
9
0.80 ± 0.32
0.8
10
0.90 ± 0.32
0.9
1
-0.30
Deaves
32
3.69 ± 4.80
0.31
31
5.19 ± 4.80
0.43
12
-0.31
Evans
117
19.40 ± 13.90
1.62
87
19.70 ± 12.60
1.64
12
-0.02
Fireman
13
0.50 ± 5.06
0.04
13
4.60 ± 5.06
0.38
12
-0.78
Hill
211
5.43 ± 4.07
1.36
193
6.23 ± 4.72
1.56
4
-0.18
Hughes
44
10.70 ± 6.90
0.89
45
16.00 ± 15.40
1.33
12
-0.44
Mitchell
133
7.92 ± 16.48
1.32
126
8.48 ± 26.69
1.41
6
-0.03
Perrin
29
0.24 ± 0.90
0.24
27
0.22 ± 1.00
0.22
1
0.02
Persaud
18
6.40 ± 4.60
1.28
18
7.60 ± 5.30
1.52
5
-0.24
Rubin
29
11.90 ± 7.80
0.99
25
15.40 ± 15.00
1.28
12
-0.30
Talabere
25
1.36 ± 2.52
0.45
25
2.60 ± 3.75
0.87
3
-0.38
Toelle
63
2.62 ± 3.28
0.44
51
2.67 ± 3.21
0.45
6
-0.02
Wilson
30
0.80 ± 2.29
0.80
29
1.40 ± 3.23
1.40
1
-0.21

* N refers to the sample size, Mean ± SD refers to the mean number of events ± standard deviation, and rate refers to the total events per person-month. ** Standardized effect size was calculated for each study by subtracting control group mean from intervention group mean and dividing by the pooled SD.

Guevara et al. BMC Medical Research Methodology 2004 4:17   doi:10.1186/1471-2288-4-17