After evaluating and testing several different data loggers, Massachusetts selected the Berlinger Fridge-tag 2 data logger for pilot testing in 2013. The following year, the program rolled out data loggers (refrigerator and freezer) to nearly 500 pediatric sites, accounting for 80% of all vaccines ordered. Upon implementation of the data loggers, the program discovered more temperature excursions than in the past. The data loggers provided an opportunity for the program to see the efficiency or inefficiency of the vaccine storage units. In 2015, the program required and supplied all pediatric providers with data loggers for their primary vaccine storage and informed providers that in 2016, a pharmaceutical grade refrigerator would be a requirement for primary vaccine storage.