Cookies and your choices

Analytics preferences

We use first-party aggregate statistics to understand which public pages are useful and how long they are viewed. Measurement runs by default under the statistical-purpose exception, with a simple, free way to turn it off here. We use the totals solely to improve the website and its resources.

Only the canonical public page path, page count and foreground viewing time enter the statistics. Signed-in visitors, private areas and likely bots are excluded. We do not create visitor profiles, record cross-page journeys or store account details, raw IP addresses, user agents, full referrers or query strings in analytics.

We temporarily use a secret-keyed IP hash specific to one page and London date to count only the first accepted visit that day, including its viewing time. These hashes cannot link pages or dates and are deleted after the following London date. We also keep broad source categories, such as Google, Facebook or email, without retaining referring URLs or campaign values. Email without source information may appear as direct. A random per-page reference stays in browser memory and a pending database record, solely to update that page's time without duplicates. It is not saved in a cookie or reused on another page. The pending record is deleted when added to daily totals. Records expire after five minutes without updates and after at most four hours; maintenance removes expired records every 15 minutes. Daily totals are kept for 13 months.

The cst_analytics first-party cookie remembers your on/off choice for six months. Local browser storage remembers the same choice and whether you dismissed the notice (cst_analytics_notice) until cleared. These preferences contain no unique visitor identifier. Dismissing the notice leaves measurement on; turning analytics off stops collection in this browser. Your choice does not affect access to resources, accounts or lessons.