As the president of popular search engine optimization firm SEO National and an international speaker on the topic of SEO, Damon Burton gets asked this question a lot: “How do I write content that will rank high on Google?”
There are all kinds of search engine optimization tools, copywriting software, and digital checkers to help copywriters measure their content and predict its success—so many, in fact, that it can be overwhelming.
“It’s nice to have options, but there are just so many tools out there that analyze different aspects of content. People don’t know what or how to measure, and some of these tools end up contradicting each other,” said Burton.
To simplify the confusion and get to the heart of what it seems Google might really want from content, Burton launched a
Since Google is famously secretive about its ranking algorithms, Burton worked backwards. He started with hundreds of search engine queries and analyzed the highest-ranking responses that made it into the top results on Google.
Burton’s team at SEO National then used 9 different metrics to analyze different features of the content like readability, syntax, word complexity/familiarity, sentence length, and overall page length. The results revealed common threads between content that ended up on page 1 in the search engine results.
Methodology
The study started with 205 search engine queries. Queries came from 4 categories, with a few examples below:
Technical Search Queries
- What is a derivative in calculus?
- What is a financial statement?
Non-Technical Search Queries
- Gluten-free diet
- Tips for surviving a flood
Silly and Random Search Queries
- Should I tell my parents I’m adopted?
- How to get out of the friend zone?
SEO Search Queries
- Good vs. bad backlinks
- Does caching help SEO?
Content Analysis
After Googling each of the 205 queries, Burton’s team collected the top 8 responses for each and analyzed them using 9 different metrics:
- Automated Readability Index
- Flesch-Kincaid Reading Ease
- Flesch-Kincaid Grade Level
- Coleman-Liau Index
- Gunning Fog Index
- Number of Words
- Number of Sentences
- Percent of Complex Words
- Average Words per Sentence
Flesch-Kincaid Reading Ease Data
This scale is often considered the Holy Grail of content metrics. It’s so popular that common SEO tools like Yoast use it to score content. However, in this study, Flesch-Kincaid results had a weak correlation with ranking success. The study showed that the higher content ranks on the Flesch-Kincaid Reading Ease scale, the lower it will appear in the top 8 search rankings. This correlation is not very strong (0.2385) but still significant enough to consider.
Best SEO Recommendation? Study results appear to show Flesch-Kincaid to be one of the least helpful measures of SEO success. If you do use the Flesch-Kincaid Reading Ease score, consider aiming for the 60-80 range (8th to 9th grade readability), as 63% of the top 8 search engine responses fell in this range.
Flesch-Kincaid Grade Level Data
This metric has a more stable correlation with high SEO rankings than the Flesh-Kincaid Reading Ease score, but it is still a negligible correlation.
Best SEO Recommendation? If you use the Flesch-Kincaid Grade Level metric, consider aiming for a score of around 6.8 (upper end of 6th grade reading). However, there’s a slightly higher threshold for technical topics. For tech writing, aim for a 7.65.
Gunning Fog Index Data
Of all the readability tests used in this study, the Gunning Fog score had the most significant correlation with high search engine ranks, making it a great metric for SEO purposes.
Best SEO Recommendation? Consider prioritizing the Gunning Fog Index for content optimization. If you use the Gunning Fog Index, target a score of at least 7.835 (readable for rising 8th graders). Aim for short sentences and non-complex words.
Coleman-Liau Index Data
As with the Flesch-Kincaid Reading Ease scale, there was little to no correlation between the Coleman-Liau score and SEO ranking.
Best SEO Recommendation? The Coleman-Liau index did not appear to correlate significantly with optimization success, but if you use it, consider aiming for a score of 11.65 (10th to 12th grade reading level), as this was the average rating for the top 8 results.
Automated Readability Index Data
There is a strong correlation between a strong Automated Readability Index score and high SEO rankings.
Best SEO Recommendation? Prioritizing the Automated Readability Index as an SEO metric looks promising. Consider aiming for an “excellent” or “good” readability score. (Lowering your words-to-sentence and characters-to-words ratios may help). Try to keep your rating at no more than 6, except for with technical topics.
Number of Sentences Data
There is a strong link between the number of sentences in a response and its search engine rank, showing that longer content tends to rank higher. The average number of sentences across the four different search categories was 258.6, showing that long-form articles still win the day when it comes to SEO.
Best SEO Recommendation? Consider aiming for long-form blogs with at least 258 sentences.
Number of Words Data
The data strongly supports that the higher the word count, the better the chance for high search engine rankings. This further supports the importance of long-form content for SEO. The average number of words varied slightly across top-ranking responses to different types of queries, with responses to silly/random being the shortest and SEO-related queries being the longest.
Best SEO Recommendation? Consider targeting an average of 1,911 words per search engine response, but silly/random content can be shorter (closer to 1,520), and SEO-related content should be longer (2,297 words).
Percent of Complex Words Data
Surprisingly, data showed that a higher percentage of complex words correlated to higher rankings, which flies in the face of conventional wisdom about using simple words in content. The average of complex words across the 4 different query categories ranged from 15% to roughly 18%.
Best SEO Recommendation? To be on the safe side, consider targeting 15 to 20% complex words. Focus on using familiar words, not necessarily short ones, as the use of multi-syllable words does not appear to drag rank down.
Average Words Per Sentence Data
Data suggests a link between shorter sentences and higher rankings, with 9.3 as the average number of words per sentence in top-ranking content.
Best SEO Recommendation? Consider keeping sentences short and sweet, roughly 9.3 words per sentence.
Key Takeaways for High-Performing SEO Content:
While the results are for educational purposes only and you should test on your own, the implied takeaways are fascinating.
What’s the Best Readability Scale?
If you want a good metric to optimize SEO, data supports the Gunning Fog Index and Automated Readability Index.
How Many Words?
Long-form content outranked short-form content. The best-performing content ranged from 1,700 to 2,300 words.
How Long Should Sentences Be?
While a higher volume of sentences tracked with a higher rank, a higher volume of words per sentence tracked with a lower rank. For best results, keep your sentence count high but your individual sentences short. The sweet spot was an average of 9.3 words per sentence.
Can I Use Big Words?
Multi-syllable words didn’t correlate with lower rankings. While Google does favor familiar words, that doesn’t necessarily mean short words. Go for familiar words, but don’t worry if those familiar words happen to have multiple syllables.
What Matters Most?
According to Burton’s study, the most statistically significant quality of high-ranking blogs was the number of sentences in blogs, with more sentences correlating with a higher rank.
The second most significant factor was the number of words per sentence, with fewer words per sentence correlating with a higher rank.
The third most significant factor was the percentage of complex words, with a certain percentage of complex words appearing to help—or at least not hurt—rankings. The familiarity of words seems to have a greater bearing on rankings than word length.
What About Technical Blogs?
If you’re writing for technical queries, you know how hard it can be to bring complex information down to a simple reading level. The good news is that rankings seem to be more forgiving of a higher readability level when it comes to technical topics. Don’t sweat it if you need to write for a slightly elevated grade level to get your point across.
Damon Burton launched his
He is a sought-after speaker, addressing crowds around the world on the topics of search engine optimization and personal branding. Burton’s upcoming circuit includes speaking at 2025’s
To learn more about Damon Burton and his ongoing quest to help clients better understand how to leverage Google, and ranking higher in search engines, call 1-855-SEO-NATL (1-855-736-6285) or go to www.SEOnational.com.
