On Monday, The Ticker reported on local health officials' concerns about a growing number of residents waiving immunizations. The statement that some Montessori schools have unusually high waiver rates compared to the overall county school district average drew criticism from some of those schools. The Ticker stands by its data and reporting, which has been reviewed and affirmed by health officials. For those looking to better understand our data, we offer the following guide to understanding state immunization records.

The Michigan Department of Community Health tracks immunization records for kindergarten students, sixth grade students (changing to seventh grade this year) and new (“other”) students to gain an overall picture of the school's immunization compliance. Of each class, students are categorized as either compliant (meaning they've received all required immunizations), provisional (meaning they're in between doses) or waived. A child can also be classified as “incomplete” if they've received some vaccinations but not all, have incomplete records or are behind in their vaccinations. Vaccines can only be waived in Michigan for three reasons: medical (a child has a contraindication to the vaccine), religious exemption or philosophical exemption (other). Provisional or incomplete students were not calculated in the waiver rates cited in our article; those rates only included medical, religious and philosophical exemptions. Of all the “temporary waivers” or reasons cited by some schools to explain their waiver rates (such as parents having incomplete records, a child being behind schedule or a vaccine being unavailable), the only explanation actually considered by the state to be a waiver is a child waiving a single vaccine (which health officials state is rare, and still poses a risk for that particular disease). All other scenarios are categorized as “incomplete” - not “waivers” - by the state.

By these state-mandated measurements, The Children's House and TCAPS Montessori do have unusually high waiver rates for their reporting classes compared to the county school average. Data for each individual school is provided in the report for those interested in researching a particular facility. Grand Traverse County Health Department Medical Director Dr. Michael Collins says kindergarten classes are “especially important, because they may show a trend before others, and because their waivers will carry through for the next several years in that school.” The school's overall population size is irrelevant, because waiver rates are calculated by percentage – whether eight students or eighty, fifty percent of a sixth-grade class waiving vaccinations poses the same risk to that particular class.

Dr. Collins also notes that the statistics in the state report are provided by the schools themselves, who must follow state reporting guidelines. If a school mistakenly records students who should be categorized as “provisional” or “incomplete” as “waivers” instead, they “run the risk of being misinterpreted,” he says. Parents are encouraged to research their schools' waiver rates, and if concerned, talk with school officials about how they arrived at those rates.