SILA models using plasma p-tau<sub>217</sub> were compared to amyloid and tau PET-based models to estimate amyloid and tau onset, and factors influencing tau onset and time from tau onset to dementia were evaluated for PET and plasma models.<h4>Results</h4>Plasma and PET models generated similar results for estimated amyloid and tau onset, with stronger model agreement for tau (r = 0.88[0.86, 0.89], t = 57.4, p < 0.001) than amyloid (r = 0.75[0.72, 0.77], t = 37.4, p < 0.001) onset. The gene discussed is MAPT; the disease is dementia.