Wagner, M. & Clayton, S. (1999). The Parents as Teachers program: Results from two demonstrations. The Future of Children, 9(1), 91-115.
1 In contrast to the study-reported results, HomVEE calculations showed this difference to be statistically significant (p ≤ 0.05). The HomVEE tests of statistical significance are based on the HomVEE calculated effect sizes, whereas authors may have used other techniques to determine statistical significance, such as regression models or analyses of variance (ANOVA).
1 Authors report that significantly more program children experienced bronchitis attacks.
Wagner, M. (2001). The multisite evaluation of the Parents as Teachers home visiting program. Menlo Park, CA: SRI International.
Wagner, M., Spiker, D., & Linn, M. I. (2002). The effectiveness of the Parents as Teachers program with low-income parents and children. Topics in Early Childhood Special Education, 22(2), 67–81.
Although some effect sizes are included in the study tables, HomVEE was unable to determine if they pertain to the one-year or two-year results and excluded the study-reported effect sizes from this table (Wagner, et al., 1996).
This table shows a study’s results by outcome measure. Rows for primary outcomes
are shaded. Favorable outcomes are listed in green and unfavorable or ambiguous
outcomes are listed in red.
This table describes in more detail the outcome measures used by a study. Rows for
primary outcomes are shaded.
Primary outcome measure: For the HomVEE review, an outcome measured
through direct observation, direct assessment, or administrative data; or self-reported
data collected using a standardized (normed) instrument.
Secondary outcome measure: For the HomVEE review, most self-reported
data, excluding self-reports based on a standardized (normed) instrument.
For a uniform approach, HomVEE calculates mean differences as the
program group mean minus the comparison group mean. In some studies, authors did
this calculation in the opposite direction.
The odds ratio is the odds of an event occurring in one group divided
by the odds of an event occurring in another group. If the odds of an event occurring
in group A equals 3 and the odds of an event occurring in group B equals 2, the
odds ratio equals 1.5. In other words, there is a 1.5 times greater likelihood the
event will occur in group A than in group B.
HomVEE reports author-calculated effect sizes when available, as labeled in the
table. If the author did not report effect sizes, but sufficient information was
available, HomVEE calculated effect sizes.
The HomVEE review calculates effect sizes using the same computations as the
What Works Clearinghouse (WWC). The WWC, established by the Institute for
Education Sciences in the U.S. Department of Education, reviews education research.
For more information, please read
WWC effect size calculations.
Statistical significance is an indication of the probability that the observed finding
was obtained by chance (when there is not a real relationship in the population).
If the p-value is equal to or less than a predetermined cutoff (in the
HomVEE review, 0.05), then the finding is considered statistically significant or
probably not obtained by chance.
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