Brian Dean recently published a voice search ranking factors study, based on the analysis of 10,000 Google Home search results, in order to understand how we should optimise for voice search.
The study investigates 11 potential factors and whether they do or don't affect results:
1. PageSpeed - Yes
The study found that voice search results pages are much faster than most webpages, with a time to first byte (TTFB) average of 0.54 seconds vs 2.1 seconds, and time to fully load of 4.6 seconds vs 8.8 seconds.
2. HTTPs Protocol - Yes
The study suggests that HTTPs might be even more important for voice search than for other devices, with 70.4% of voice search result URLs using HTTPs compared to 50% of Google desktop searches.
3. Voice Search Answer Length - Yes
The data collected shows that the average voice search answer is 29 words long, hitting the right balance of being informative and concise, all at the same time.
4. Schema Mark-Ups - No
Only 36.4% of the voice search result pages within the study were using Schema mark-ups (vs 31.3% for the average webpage), so it looks like Schema isn't a differentiating factor.
5. Strong Domain Rating - Yes
The study analysed the Domain Rating and Page Rating (Ahref metrics) of every result and discovered that while page ratings were of little importance, the average Domain Rating was 76.8 (considerably high).
6. Social Engagement - Yes/No
While it's unlikely that the voice search algorithm uses social engagement as a factor, a correlation between highly shared content and voice search results was found, with an average social share count of 1,199 (vs 2 for the average web page).
7. Readability - Yes
The easier your web page is to read, the easier your content will be returned on voice search results - a 9th grade level will do on average.
8. Keywords In Title Tag - No
Only 1.71% of voice search results use the query exact keywords in the page title tag, highlighting little correlation between the two.
9. Content Length - Yes
The study highlights how results tend to come from pages with a high word count. In fact, the average content length is 2,312 words. This could be because long content has a greater chance of ranking for more queries, but it still means that producing long content is preferable to creating different pages with shorter content. The study also points out how well FAQ pages perform for this search type.
10. High Rankings - Yes
Similar to Featured Snippets, there's a higher probability for pages with high rankings on other devices to be used for voice search results. More than 60% of the results, in fact, appeared in position 1-2 for desktop searches.
11. Featured Snippets - Yes
And on the subject of Featured Snippets, yes, there's a high correlation between these and voice search results too, with 40.7% of results pulling from a Featured Snippet. Featured Snippets, in fact, are the perfect voice search result: short, informative, and pulling from high-ranking authoritative sites.
While some of the results might seem obvious, they're helpful to consider when creating a voice search-focused strategy and related recommendations going forward.