OBJECTIVE: Seizure control is often assessed using patient-reported seizure frequencies. Despite its subjectivity, self-reporting remains essential for guiding anti-seizure medication (ASM) decisions and ongoing patient investigations. This study aims to compare patient-reported seizure frequencies with electrographic frequencies captured via ambulatory video EEG (avEEG). METHODS: Data from intake forms and seizure diaries were collected from patients undergoing home-based avEEG in Australia (April 2020-April 2022). Intake forms included monthly seizure frequency estimates. Only avEEG-confirmed epilepsy cases were analyzed. Univariate and multivariate analyses compared seizure frequencies reported via EEG, diaries, and surveys. RESULTS: Of 3,407 reports, 853 identified epilepsy cases, with 234 studies analyzed after excluding outliers. Diary-reported frequencies correlated with EEG frequency (p <
0.00001), but survey-reported frequencies did not (p >
0.05). Surveys significantly overestimated true seizure frequency (median = 3.98 seizures/month, p <
0.0001), while diaries showed substantially smaller differences (median = 0.01 seizures/month, p <
0.0001). Carer presence was associated with higher diary-reported frequencies (p = 0.047). Age negatively correlated with survey frequency estimation error (p = 0.016). Multivariate analysis identified age and carer status as significant predictors of residuals. CONCLUSIONS: Most patients overestimate their true seizure frequency, potentially influencing therapeutic decisions and raising concerns about the reliability of some participants and carers to self-report seizures in clinical trials. SIGNIFICANCE: An "over-reporting, over-prescribing" cascade may affect epilepsy treatment and highlights the potential issue of clinical drug trials relying on self-reported seizure rates for primary endpoints.