My site is not Quantified but the numbers for my site don’t align with my internal statistics — why?

If your site is not Quantified, then we’re only able to present estimates for your audience. These estimates are only as accurate as traditional panel-based measurement services, as we are relying solely on third-party data. Quantcast’s system is collaborative and sites can participate in our continuing effort to offer the most accurate data available by getting Quantified, free of charge. Quantcast Measure incorporates your real site traffic into the audience calculations, thus offering the highest degree of accuracy.