Optimizing Meta Descriptions, H1s and Title Tags: Lessons from Multivariate SEO Testing at Etsy
We recently ran a successful split-testing title tag experiment to improve our search engine optimization (SEO), the results and methodology of which we shared in a previous Code as Craft post. In this post, we wanted to share some of our further learnings from our SEO testing. We decided to double down on the success of our previous experiment by running a series of further SEO experiments, one of which included changes to our:
- Title tags
- Meta descriptions
We found three surprising results:
- Shortening our title tags showed improved performance in terms of visits (and other key metrics)
- Meta descriptions had a statistically significant impact on organic search traffic
- H1s had a statistically significant impact on organic search traffic
Some notes on our methodology
For full details on the setup and methodology of our SEO split testing methodology, please see the previous Code as Craft post referenced above.
For this particular test, we used six unique treatments and two control groups. The two control groups remained consistent with each other before and after the experiment.
To derive the exact estimated causal changes effected in visits, we most often used Causal Impact modeling as implemented in the CausalImpact package by Google to standardize the test buckets against the control buckets. In some cases, the difference in differences method was used because it was more reliable in estimating effect sizes when working with strong seasonality swings.
This experiment was also impacted by strong seasonality and external event effects related to the holidays, sports events and the US elections. The statistical modeling in our final experiment analysis was adjusted for these effects to ensure accurate measurement of the causal effects of the test variants.
Takeaway #1: Short Title Tags Win Again
The results of this experiment aligned with the findings from our previous SEO title tag experiments, where it appeared shorter title tags drove more visits. We have so far validated our hypothesis that shorter title tags perform better in title tags in multiple separate experiments including many different variations and now feel quite confident that shorter title tags perform better (as measured by organic traffic) for Etsy. We hypothesize that this effect could be taking place through a number of different causal mechanisms:
- Lower Levenshtein distance and/or higher percentage match to target search queries rewarded by Google’s search algorithm and thereby improving Etsy’s rankings in Google search results. Per Wikipedia: “the Levenshtein distance between two words is the minimum number of single-character edits (i.e. insertions, deletions or substitutions) required to change one word into the other.”
- Shorter title tags, consisting only of the target search keyword, appear more relevant/enticing to search users
Takeaway #2: Meta Descriptions Matter
We found that changes in the meta description of a page can lead to statistically significant changes to visits. It appeared that longer and descriptive meta descriptions performed better and that conversely, shorter, terse meta descriptions performed worse. We hypothesize that longer meta descriptions might perform better via two possible causal mechanisms:
- Longer meta descriptions take up more real estate in a search results page, improving CTRs
- Longer meta descriptions give an appearance of more authority or more content, improving CTRs
Takeaway #3: H1s matter
We found that an H1 change can have a statistically significant impact on organic search traffic. However, changes in the H1 section of a page appear to interact with changes in title tags in hard to predict ways. For example, in this experiment, a title tag change in a certain variant increased visits. However, when the title tag change was combined with an H1 change, the positive effect of the title tag change was dulled, even though an H1 change by itself in a different variant led to slight increases in visits. This highlights the importance of SEO testing before rolling out even seemingly minor changes to Etsy pages.
Accounting For Unexpected Events
The Donald Trump Effect
One example of an event we had to control for (among a number of others) was the “Donald Trump effect”. We observed a large bucket skew on November 9 and 10, 2016 in one of our test groups. Upon investigation, it was found that the skew was due to large increases (+2000% to +5180%) in daily visits to pages related to “Donald Trump” the day after the US Presidential elections. Although the spikes in traffic to these pages were short lived, lasting only several days, they nevertheless did have the potential to unduly bias or reduce the statistical significance of the results of our experiment. These pages were therefore removed and controlled for when conducting the causal impact analyses for this experiment.
Our SEO experiments illustrate the importance of running SEO tests before making changes to a web page and continue to offer surprising results. However, it is important to note that the results of our experiments are only true for Etsy and do not necessarily reflect best practices for sites generally. We would therefore encourage everyone to discover the strategy that works best for their website through rigorous SEO testing.