After indexing both the Lean audit data and the performance
data, we have (approximately) 86 cases for further
analysis (i.e., 86 data points for each regression analysis).
The total number of useable Lean audit reports for further
analysis was 100. These 100 cases represent slightly less
than four years, lasting from around 2005 to 2009, with
quarterly Lean audit reports. We lost 14 cases due to the
calculation of the baseline-indexes (seven value streams
times two base numbers per stream). Eighty-six data points
is an adequate sample size, as the regression analysis made
below has significant test results, and because analysis
of statistical power 4 revealed no problems related to the
regression analysis presented in Table 5.