Meta-Essentials is a set of seven different workbooks, each for meta-analysing a different type of effect size (which are explained shortly hereafter). Although the workbooks look the same, the calculations ‘behind’ them are different. From the user’s perspective the most noticeable difference is that the workbooks require different inputs. An overview of the different workbooks is given in Table 1.
|File name||Type of effect||Example|
|1. Effect size data.xlsx||Any, as long as directly comparable||Abnormal returns of bank loan announcements.|
|Group differences||2. Differences between independent groups - binary data.xlsx||Difference between two independent groups with binary outcome|
Counts of start-ups that did survive and did not survive after three years per gender of entrepreneur:
|3. Differences between independent groups - continuous data.xlsx||Difference between two independent groups with continuous outcome||The difference between the average sales of a team that received training and that of a team that did not receive training.|
|4. Differences between dependent groups - continuous data.xlsx||Difference between two dependent groups with continuous outcome||The difference between the average sales of a team before and after receiving a training.|
|Relationships between variables||5. Correlational data.xlsx||Correlation between two variables||Relationship between investments in computer technology and business performance|
|6. Partial correlational data.xlsx||Relation between two variables, controlled for other variable(s) in both predictor and outcome||Idem, but controlled for type of technology.|
|7. Semi-partial correlational data.xlsx||Relation between two variables, controlled for other variable(s) in outcome||Idem, but controlled for average industry performance.|
Table 1: Overview of the Meta-Essentials workbooks
Workbook 1, ‘Effect size data.xlsx’, can be considered the generic one. This workbook can be used when the user has (1) the point estimate of the effect size and (2) its standard error. The effect sizes of the different studies must be comparable or, in other words, they must be sizes on the same scale. Workbook 1 can only be used for effect sizes on a continuous scale on which the intervals have the same weight or meaning at every point on the scale. This scale can be an unstandardized one (such as millimetres, minutes, grams, dollars, regression weights, etc.) or a standardized one (Cohen’s d, Hedges’ g). Intervals between standardized regression weights and between correlation coefficients are not the same in this sense, and hence the generic workbook 1 cannot be used for meta-analysing that type of effect size. Workbooks 5, 6 and 7 can be used for meta-analysing correlation coefficients and results of a multiple regression analysis.
Workbooks 2 to 7 are basically extended versions of workbook 1. They perform calculations and transformations that precede the meta-analysis proper. These include calculations of effect sizes of studies that do not report them, and transformations of effect sizes to more suitable scales. Each one of the workbooks 2 to 7 does this for a specific type of effect size. To decide which workbook you should use, you must first determine whether your effect size is of the ‘difference family’ or of the ‘correlation family’. The difference family, or d-family, regards effect sizes that are based on differences between or within groups; you can use workbook 2, or 3 or 4. The ‘correlation family’, or r-family, regards effect sizes based on the association between two (or more) continuous variables; you can use workbook 5, 6, or 7.
If your effect size is of the d-family, you can find guidance about how to make a choice between workbooks 2, 3 and 4 in the following section. If your effect size is of the r-family, you can find guidance about how to make a choice between workbooks 5, 6 and 7 in the section thereafter.