Google not only has totally unique SERP features on mobile, but also quite often trends those that also appear on desktop differently than it does on mobile. The fundamental premise of this study is that by isolating the instances where Google diverges from its desktop SERP feature patterns, the search engine's entire stance on the mobile web slowly emerges. Working under the assumption that any mobile data divergence is purposeful and meaningful, mobile's unique SERP feature trends work to illuminate Google's overall relationship to the mobile SERP.
Desktop Vs. Mobile SERP Data Dive
As part of the effort to isolate Google's overall mobile SERP philosophy, trends for the following SERP features were analyzed both in the US and the UK for both desktop and mobile:
Average Organic Results per Page
In reference to the above data-sets, only data for Page One of the SERP was analyzed. Further, the data collected was for a period that ran from January 1, 2017 - August 31, 2017. Using the numbers as of August 31, 2017, what will be referred to as the Relative Rate between the desktop and mobile SERP feature data was determined.
The Relative Rate used throughout the study refers to the increase in the relative frequency in which Google displays a SERP feature from one device to the next. For example, should Google show more Local Packs on desktop than on mobile, the Relative Rate would be the increase in the frequency with which Google shows Local Packs on desktop relative to mobile.
As such, the data is as follows:
Image Thumbnails Page One Appearance:
US Desktop: .34% of all Page One SERPs US Mobile: 8.59% of all Page One SERPs
Relative Rate: 2,426% increase in the frequency in which Google shows the feature on mobile relative to desktop.
UK Desktop: .11% of all Page One SERPs UK Mobile: 13.39% of all Page One SERPs
Relative Rate: 12,072% increase in the frequency in which Google shows the feature on mobile relative to desktop. (The normal Relative Rate for this feature in the UK sits at about 5,000%, the 12,000% indicated is the result of a one time data spike).
Video Thumbnails Page One Appearance:
US Desktop: 7.6% of all Page One SERPs US Mobile: .35% of all Page One SERPs
Relative Rate: 95% increase in the frequency in which Google shows the feature on desktop relative to mobile.
UK Desktop: 6.22% of all Page One SERPs UK Mobile: .18% of all Page One SERPs
Relative Rate: 97% increase in the frequency in which Google shows the feature on desktop relative to mobile.
Carousels Page One Appearance:
US Desktop: .66% of all Page One SERPs US Mobile: 3.35% of all Page One SERPs
Relative Rate: 408% increase in the frequency in which Google shows the feature on mobile relative to desktop.
UK Desktop: .63% of all Page One SERPs UK Mobile: 2.25% of all Page One SERPs
Relative Rate: 257% increase in the frequency in which Google shows the feature on mobile relative to desktop.
Note: Google displays another form of carousel on mobile, Rich Cards. At the end of the data collection period, Rich Cards showed on 6.4% of mobile Page One SERPs in the US and on 7.2% of those in the UK. As such, the total Page One carousel appearance on mobile is:
Knowledge Panel Page One Appearance:
US Desktop: 8.1% of all Page One SERPs US Mobile: 7.5% of all Page One SERPs
Relative Rate: Marginal difference
UK Desktop: 6.6% of all Page One SERPs UK Mobile: 6.4% of all Page One SERPs
Relative Rate: Marginal difference
Local Pack Page One Appearance:
US Desktop: 42.4% of all Page One SERPs US Mobile: 34.5% of all Page One SERPs
Relative Rate: 18.5% increase in the frequency in which Google shows the feature on desktop relative to mobile.
UK Desktop: 18.75% of all Page One SERPs UK Mobile: 19.78% of all Page One SERPs
Relative Rate: 5.5% increase in the frequency in which Google shows the feature on mobile relative to desktop.
Questions Based Upon Desktop Vs. Mobile Google SERP Feature Trends
Why are there more Image Thumbnails on mobile than on desktop?
Why doesn’t this trend apply to Video Thumbnails?
Why does Google prefer to show more carousels on mobile?
Why are Rich Cards that much more prevalent than traditional mobile carousels?
Why aren’t Knowledge Panels limited on mobile considering they occupy space within organic results on mobile (and considering that Google does restrict Local Packs when space is limited as seen within the data out of the US)?
Explaining Google's Mobile Strategy
Using the data listed above, an overall approach to how Google views the mobile SERP was formulated. This theory will now be used to explain the above listed questions.
Digital Touch Research
Research as to the psychological nature of digital touch devices will provide a foundation to the theory outlining Google's mobile strategy.
Google understands that due to the unique relationship between a mobile device and its user (see research section above), that the mobile SERP is primed for deep user engagement. Knowing this, Google has consciously formatted the mobile SERP according to the underpinnings that make an app highly engaging, i.e. visually focused and deeply layered content. In doing so, Google meets the user's precognitive expectation of being more deeply engaged on the mobile SERP. That is, Google, like the NIH, understands that the user is inherently more engaged on a touchscreen device like a mobile phone, and has crafted a SERP that meets the expectation of and natural predisposition towards increased engagement.
As such, and in answering the above listed questions:
1) Google specifically shows more Image Thumbnails on mobile as means of creating a more visually orientated mobile SERP. Google specifically stated so in September of 2016. By doing so Google enables the user to more deeply stimulated and engaged (in line with the research out of the NIH, etc.).
2) Video Thumbnails, though visually stimulating, do not fit Google's mobile SERP scheme. As opposed to desktop, engaging a Video Thumbnail on mobile results in a new app opening (YouTube) and the user entering an entirely new ecosystem. Doing so creates a disconnect, disassociation, and an overall break in the mental flow needed to foster deep user engagement. As such, desktop shows more Page One SERPs with Video Thumbnails than mobile.
3) More SERPs contain carousels on mobile since like Image Thumbnails, the feature is visually stimulating thereby fostering the expected level of mobile engagement. Carousels however incorporate two other engagement engendering elements. Specifically, carousels demand the user physically engage the SERP via a swiping action and offer increased cognitive engagement via a longer and more in-depth series of content (as compared to an Image Thumbnail). 4) Extending that which was elucidated regarding carousels, of all carousel formats, Google prefers to show the Rich Card format. This is logical considering that Rich Cards are more engaging than the traditional mobile carousel in that its images are larger (and thereby more engaging). Additionally, Rich Cards contain ancillary content, and as such, offer a deeper and therefore more engaging cognitive experience when compared to traditional mobile carousels.
5) While Google does limit Local Pack's display frequency on mobile, it does not do so for Knowledge Panel. Local Pack sees a limitation when there are less organic results on more pages as the intention of the user is not to be engaged, but rather, to receive a limited set of options in order to make an actionable decision (i.e. where to eat, etc.). Knowledge Panel on the other hand is the perfect tool for increased engagement on the mobile SERP. This is because mobile Knowledge Panels are:
Visually diverse in their appearance (and contain images as well).
Contain multiple functionalities (i.e. carousels, tabs, buttons, etc.) with which the user interfaces with the feature.
Offers an extensive array of content to engage the user with and that frequently results in the user moving from one panel to the next.
As a result of the above, mobile Knowledge Panels present the most ideal way to capitalize on mobile's increased user engagement. To this extent, Google does not limit their appearance on the mobile SERP, despite the organic space the feature occupies on mobile.
The Overall Takeaway from Google's Mobile Strategy
Much has been said about the increased number of mobile searches. This quantitative uptick is widely held to be the reason behind Google's mobile-centered focus. However, there is a strong case to be made that it is the qualitative advantage that is the primary force behind Google's mobile centrality. Specifically, capitalizing on the engagement possibilities that mobile offers is an attractive allurement that is moving Google's mobile momentum.
To that extent, SEOs and site owners may wish to take the following actionable steps:
Monitor Google's constant testing of mobile SERP features.
Aim for rich content (i.e. Image Thumbnails, Structured Snippets, etc.).
Optimize to convert from the SERP itself in a strategic manner.
Ensure that a business has positive reviews as numerous ratings appear within a mobile Local Panel before it is expanded.
Take advantage of the custom content Google allows you to place within the Knowledge Panel (i.e. Google Posts, question and answer placement, etc.).