Artificial intelligence may be the future (and present) of how search engines work, but for now, Google still hires people to look at webpages and rank them on a 5-point scale from lowest-quality to highest-quality. Why? Because even AI needs to be taught what is good and bad.
These human ratings don't directly impact Google's search rankings, but they're a way to check an algorithm's work to make sure that legit sites don't get punished with the bogus ones, and vice-versa.
The good news for publishers and webmasters is that Google openly publishes its "Search Quality Evaluator Guidelines." The PDF is between 150-200 pages long and is updated periodically.
This document evolves from one version to the next and Jeniffer Slegg at The SEM Post does a great job of highlighting these changes. But, some things haven't changed much over the years and are unlikely to change in the future. That's what I'd like to highlight here.
Things to Know
Some websites are held to a higher standard - Google places more scrutiny on content that can affect a person's health, wealth or happiness.
Sites that don't look trustworthy are treated as such - Things like sleazy advertisements, comment spam, broken formatting and other sketchy looking things guarantee a low quality rating.
A bad reputation is a recipe for a low quality rating - Great content on a website with a terrible reputation may receive the lowest quality score. A bad rep drags a whole site down.
High quality content can become low quality content - Webpages that aren't updated with new information will lose quality over time. This is especially true for financial and medical topics.
Low effort articles are low quality articles - The quality of a webpage is proportional to the effort that it takes to create it. High quality content must add some kind of value.
High quality articles are authored (or supported) by an expert - Things like financial and medical advice should be written by, or include quotes from, an accredited expert. "Real world" expertise is acceptable for other topics (e.g. a family travel blog or a product review website).
Every page should have a clear purpose - A high quality webpage should help the user know something, do something or go somewhere.
Buggy, broken or hard to use pages are low quality - High quality sites are regularly maintained and offer a functional experience. This is especially true for large publishers.
Life experiences are considered real-world expertise - Authors can be an "expert" when they have lived through something and shared their experience (e.g. survivors' tales).
Publishers are responsible for everything on a site - A website is responsible for the content within comments, advertisements, syndicated stories and user-generated content.
Things to Do
Check for broken images and links;
Demonstrate personal or professional expertise;
Quote credentialed experts when appropriate;
Update articles with new information;
Create a masthead and/or author biographies;
Add helpful related content to a page;
Flag or delete spam within comments;
Engage respectfully with readers;
Syndicate cautiously from other sites;
Report distracting or deceptive ads;
Make pages easy to read and use;
Fix or report broken pages or errors;
Choose trust-inspiring imagery;
Take bad press and negative feedback seriously;
Publish new content regularly; and
Don't let landing pages look stale or abandoned.
Want to hear something crazy? Despite the reams of instructions that Google has for its quality raters, the document basically says, if in doubt, trust your gut. That means the "quality" of your webpage can hinge on how a stranger perceives it.
The list below is a rehash of the points above, but through a negative lens:
Things to Avoid
Stale landing pages;
Lack of supporting content;
Deceptive page design;
No contact information;
Malicious or misleading ads;
Overly commercial content;
Bad mobile experience;
Hard to read pages; and
Typos and formatting bugs.