At each stage of contact, parents who declined were asked their reasons for non-participation, consistent with the STROBE guidelines [ 39].
Despite our low attrition rates, we identified several determinants of selective participation consistent with previous research.
The variables of "gender", "ethnicity", "education", "monthly income" were not significantly associated with participation, consistent with some previous literature [ 32].
In our study, we found a relation between health promoting resources and work participation, consistent with theoretical assumptions.
Two waves of survey distributions, followed by a non-responder survey, were used over a nine week period to promote participation, consistent with a modified Dillman technique [ 10].
Public participation is consistent with the three-dimensional concept of sustainable development as it allows natural capital to be traded off for economic and social capital.
The incorporation of activities and participation is consistent with the International Classification of Functioning, Disability and Health, which is the WHO's framework for measuring health and disability (http://www.who.int/classifications/icf/en/).
Thus, OLS seems to overestimate the effect of grandparental childcare on mother's labor force participation, which is consistent with the existence of significant differences in characteristics seen in Table 1.
The age distribution and participation rates are consistent with the other OCAC studies (Table 1).
In a section on lessons learned, the inquiry states: "Where the UK is the junior partner and is unable during the planning or implementation to secure the outcome it requires, it should take stock of whether to attach conditions to continued participation and whether further involvement would be consistent with the UK's strategic interests.
The students' participation was voluntary and consistent with the procedures of the university research review boards.
