In contrast to the GMTF study, the two U.S. based studies were considered effective.
Some potential approaches to further investigation of the relationship between asthma and ozone, including those that would link controlled human exposures to population-based studies, are considered.
The three proxies above which are also standard proxies for information asymmetry based on previous studies are considered sufficient to conclude on our research hypotheses.4.4
Where studies are considered similar enough (based on consideration of populations, interventions or other factors) to allow pooling of data using meta-analysis, we will assess the degree of heterogeneity by visual inspection of forest plots and by χ test for heterogeneity.
Peer-reviewed publications, grey literature and baseline data from population based intervention studies were considered for inclusion.
For the RfC, three studies were considered based on different study designs and toxicological endpoints, including neurotoxicity, systemic toxicity, and potential developmental and reproductive toxicity.
All aggregates tested in this study were considered as reactive based on the above mentioned 14-, 28- and 56-day failure criteria.
One unpublished study was considered for inclusion, based on published work concerning the methodology of the study.
Five different p-value based methods are considered in this study; the details of these methods can be found in the original publications that introduced them.
However, because these risk estimates are based on epidemiological studies, they are considered somewhat more certain.
For example, in the health sector, systematic reviews of studies that are based on randomised trials are considered the most robust evidence.
