I doubt that the respondents were able provide sufficiently complete and reliable information about oral statements to make such an analysis meaningful. With these assumptions in mind, we can now turn to the data. This difference in proportions is not statistically significant at ordinary confidence levels. Perhaps these judicial suggestions have influenced Michigan employers ' contractual practices. Cross-tabulations by size suggest that employment contracting behavior does vary systematically with the number of employees at a company.
Contractual behavior varies only slightly across three broad industry groups.
The services group is somewhat less likely to have no documents concerning discharge, and slightly more likely to contract for just cause. The retail and wholesale trade group is more likely to have no documents and just slightly less likely to contract explicitly for employment at will. At finer levels of aggregation, the only systematic pattern by industry is that not one of the 21 law firms in the sample provides just cause protection. Finally, contract choices do not seem to be influenced by whether the employer has some unionized employees. And in part because the sample includes only 18 employers with union employees, these differences are not statistically significant.