Diagnosing A Sudden Rank Drop

I woke up this morning to find that my main affiliate site has lost about 60% of its organic traffic. I haven't changed anything on the site for months, so I am completely lost. Is this a penalty or just a fluctuation? I need a checklist to figure out what went wrong before I start panic-deleting pages.

The first rule is not to panic, as knee-jerk reactions often make it worse. You are likely dealing with a Core Update which targets content relevance rather than technical errors. I recommend reading this guide: https://revenuelab.biz/blog/articles/how-to-deal-with... It outlines a specific workflow for diagnosing the drop, including checking for manual penalties and analyzing which specific pages lost value.