The health plan population will be identified through enrollment and claims data from Harvard Pilgrim Health Care (HPHC). Eligible patients will include adults aged 18-64 and children aged 4-17 years with a diagnosis of asthma. Patients will be selected if they have been enrolled in an employer-sponsored HSA-HDHP with or without a PDL, or a traditional plan without a high deductible, for the prior year. Among those eligible in each sub-group, the investigators will randomly select 9 from each cell to send a recruitment mailing, for a total of 81 patients or parents invited to participate.