The data that was collected was analyzed using the meta-analysis method

The data that was collected was analyzed using the meta-analysis method (Griffin et al., 2005). This method involves the comparison of standardized measures of two different relationships. First, we have the relationship between the offspring sex ratio, denoted by sex, and the number of helpers in a group. This relationship assesses how far the parents overproduce the helping sex when the particular sex is rare or absent in a given social grouping. The second method is the relationship between the production of offspring or survival and the number of helpers, denoted by help. This one assesses the benefit of having helpers. Extreme positive values show that either there is stronger overproduction of the helping sex when they are rare or a much greater fitness benefit due to the presence of helpers which implies a positive correlation between the two. More advanced versions of the standardized values were also used. These two methods are appropriate for the hypothesis since the approaches are good approximations and can easily help in drawing meaningful deductions especially for the fact that effect sizes vary between species.