Table 1.

Characteristics of the AMPP and CaMEO Studies

	AMPP	CaMEO
Sample source	Research panel of households	Research panel of individuals
Data collection method	Mailed questionnaire	Web‐based survey
Sampling method	Demographically representative panel	Quota sampling from a demographically representative panel
Study design	Longitudinal study with cross‐sectional surveys	Longitudinal study with cross‐sectional surveys
Baseline study year	2005	2012
Duration	Annually over 5 years	Quarterly over 15 months
Cases screened	Severe headache	Headache
Survey response rate, %	64.8/77.1*	16.5
Diagnostic criteria	Modified ICHD‐2†	Modified ICHD‐3 beta
Diagnosis ascertained by	AMS/AMPP diagnostic module15, 16	AMS/AMPP diagnostic module15, 16
Baseline migraine sample size, n	12,043	16,789
CM, n (%)	794 (6.6)	1,476 (8.8)
EM, n (%)	11,249 (93.4)	15,313 (91.2)
Data focus	Headache‐day frequency	Headache‐day frequency
	Disability	Disability
	Healthcare utilization	Healthcare utilization
	Medication use	Medication use
	Diagnosis rates	Treatment satisfaction
	Headache severity	Barriers to medical care
	Allodynia	Comorbidities
	Lost productivity	Quality of life
	Comorbidities	Family burden

*The response rate to the initial household screening study was 64.8%, and response to the baseline longitudinal study was 77.1%.

†Only ICHD‐2 symptom criteria were available in 2005; however, ICHD‐2 and ICHD‐3 beta are similar with respect to symptom criteria and case selection for migraine. Inclusion criteria are considered a modification of ICHD‐3 beta because 2 criteria were not confirmed: ≥5 lifetime migraine events (criterion A) and duration of attack untreated from 4–72 hours (criterion B).

AMPP, American Migraine Prevalence and Prevention; CaMEO, Chronic Migraine Epidemiology and Outcomes; CM, chronic migraine; EM, episodic migraine; ICHD, International Classification of Headache Disorders.