Post-Migration Sitemaps: 1.7x More Bad URLs Than Average

    On redirects and client errors, 7.3% of sampled sitemap URLs on 361 replatformed sites are bad, against 4.3% on 219 comparison sites, a 1.7x gap. Adding canonical and noindex checks on a subsample, 11.4% of listed URLs should not be in the sitemap.

    Sitemap URLs that redirect or error, switchers vs full-crawl sites
    Platform switchers (361 sites)7.3%
    Full-crawl sites (219)4.3%

    Source: PageSpeed Matters, Oct 2026. Sitemap URLs requested without following redirects.

    Redirects and client errors only; canonical and noindex are not included.

    Source: Post-Migration Sitemaps: 1.7x More Bad URLs Than Average - PageSpeed Matters