In the context of choice of childcare, maternal age is used as a more specific variable, although its effect is sometimes significant (Barnes et al. 2006), it mostly is not (Fram and Kim 2008; Sylva et al. 2007; Zachrisson et al. 2013).
In both approaches consideration of the compatibility of studies in terms of design, as well as specific variables, is paramount.
Because many studies in the repository are longitudinal in nature, an important future development would be preparation and inclusion of additional time points as well as specific variables.
Identifying causes of rate heterogeneity as well as specific variables that affect underlying mutation and substitution rates is fundamental to understanding the mechanisms that cause evolution of DNA sequences (reviewed in [ 7]).
For example when modeling breeding season success, we might want year as a specific explanatory variable.
Therefore, it is important to know if the short-term training program, as a specific training variable, could improve muscle mass in untrained older adults.
As a domain-specific variable, opinion leadership affects others' adoption decisions, attitudes, and opinions via interpersonal communications (Tellis et al. 2009).
Most importantly, the model includes ∆bw% as a pair-specific variable assuming that the degree of birth weight discordance, i.e. quantitative discordance, affects the extent of intra-pair difference in DNA methylation level.
Factors such as club, and attendance can influence how students feel about their SE, as well as more classroom specific variables such as the nature of the task, or the composition of the group.
