We select these years of data because they have consistent information on key variables across time.
Differences were observed at baseline, with the experimental group having significantly lower scores than the control group on key variables.
First, different UK regions may not attract groups of Polish immigrants that differ significantly on key variables affecting participation.
Scenarios are basically built on the basis of a what-if logic, by making some assumptions on key variables.
An advantage of non-parametric matching is that treated and controls are matched on key variables of interest.
A detailed economic analysis on the chosen scenario is also conducted on key variables, such as, oil prices, price of injectant (CO2), capital expenditures and operating costs.
We pool together 4 waves: 1995, 1998, 2000, 2002 since these overlap with our sample period and include consistent information on key variables.
Having eliminated observations with missing values on key variables, the final sample consisted of 9,963 observations on 6,446 individuals.
We sought to identify the relative sensitivity of mechanical fretting to a comprehensive set of parameters such that attention may be focused on key variables.
In a previous analysis (Gielen, et al. 2013), we showed that our standard and enhanced neighborhoods were comparable to each other on key variables (e.g., income below poverty, education), but were poorer and less well educated than Baltimore City as a whole.
Other than implementing Heckman probit models to address this issue statistically, we performed standard checks to identify patterns of missingness and, similar to other recent analyses of the SVORI data (Link & Roman, 2017; Stansfield, Mowen, O'Connor, & Boman, 2016) did not find significant differences between attriters and nonattriters on key variables in our analysis.
