Using a stratified random sample design, NORC selected the sample states and carriers (Table 3). States were organized into three strata: (1) states with MLR guidelines in 2010, (2) states without MLR guidelines in 2010, and (3) states that do not require carrier filings. Five states (Alaska, Georgia, Missouri, Montana, and Louisiana) were in the third strata and were excluded from the sample.
The remaining states were selected as follows within the two strata (states with and without MLR guidelines):
- In each stratum, determine the share of the total stratum enrollment for the states included.
- In each stratum, order the states from largest to smallest in terms of their share of the total enrollment in the stratum.
- Expect states with a proportion greater than a uniform selection probability (greater than 5% for the first stratum and greater than 10% for the second stratum) to be automatically selected. Those states will be removed from the selection process and the remaining states will be redistributed.
- Choose a random start point and systematically select the remaining states.
Table 3 provides a listing of the final selected states. The inability to download data from Texas, Tennessee, South Carolina, New York, and Mississippi, resulted in their exclusion from the sample. Kentucky, Arkansas, Oklahoma, Maine, and Nebraska replaced the five excluded states.
Table 3: State Sample Design and Selection
|Stratum||State Does Not Require Filings||Established MLR Guidelines as of 2010||No MLR Guidelines as of 2010|
|Initially Selected States in Final Sample||CA, CO, CT, FL, IA, KS, MD, MA, MI, MN, NJ, NC, OH, OR, PA, SD, VA, WA||AL, HI, ID, IL, IN, RI, WI|
|Initially Selected States Dropped from Final Sample||NY, SC, TN||MS, TX|
|Initially Excluded States Added to Final Sample||AR, KY, ME, OK||NE|
|Initially Excluded States not in Final Sample||AK, GA, MO, MT, LA||AZ, DE, NH, NM, ND, UT, VT, WV||DC, NV, WY|