Does Schema Markup Actually Impact Search Rankings?
A 10-week controlled experiment reveals the truth about schema's SEO impact.
1The Great SEO Debate
The impact of schema markup on search rankings has been a longstanding debate in the SEO community. Google officially states that schema only affects appearance through rich snippets and contextual understanding. However, many experts believe that if Google recommends structured markup, it must confer ranking benefits. Anecdotal evidence and correlation studies on LinkedIn seem to support both sides. But most of these studies suffer from small sample sizes or fail to control for independent variables, making their conclusions unreliable.
2Unique Experimental Design
Evergrow Marketing conducted a 10-week controlled experiment with 29 landscaping and lawn care businesses. All participants were similar in scale, using the same WordPress theme with only localization differences. The study divided subjects into control and test groups - the control group received no intervention while the test group had LocalBusiness schema added. Geographic location and seasonality factors were evenly distributed to ensure reliable results. This homogeneous sample provided ideal conditions to isolate schema's pure effect.
3Critical Schema Selection
Choosing the right schema type was crucial for the experiment's validity. Schema types that could generate rich snippets like FAQ or reviewRating were intentionally excluded. This ensured any ranking changes would be due to schema's presence rather than enhanced CTR from snippets. The LocalBusiness markup from schema.org was selected after consulting with Yoast and Moz experts. This schema type could be consistently applied across all businesses while minimizing rich result potential.
4Pre-Experiment Preparation
Before the experiment began, all existing schema markup was removed from participant websites - including Yoast's native breadcrumb schema. Google Search Console verified proper indexing without schema. A 5-week stabilization period followed schema removal to eliminate any lingering effects. This meticulous preparation created a clean baseline for measuring schema's impact. The attention to detail in this phase was critical for isolating variables and ensuring data integrity.
5Testing Protocol Implementation
During the 5-week test period, LocalBusiness schema was added only to the test group while both groups had all other SEO activities paused. Benchmark reports were created at the start and end. Ranking data was tracked separately for Google, Google Mobile, Bing and Yahoo. Data came from 18 different Google Business Profile locations. Seasonal effects were balanced by including equal numbers of northern and southern U.S. businesses in each group.
6Overcoming Technical Challenges
The study faced significant challenges from the landscaping industry's seasonal nature. Conducted February-April, northern clients were emerging from winter while southern ones had different patterns. Although all clients used the same WordPress theme, minimizing content and image variations required careful planning. The team received special training to ensure consistent schema implementation. Moz Local dashboard helped manage multi-location data collection efficiently across different markets.
7Rich Snippet Considerations
Google's August 2023 removal of FAQ rich snippets significantly influenced the experiment design. Only government and health organizations could now use them. Therefore, schema types that might generate snippets (like priceRange or reviewRating) were deliberately excluded. This ensured results would reflect schema's direct impact rather than secondary rich result effects. LocalBusiness schema has minimal rich snippet potential, making it ideal for testing schema's pure ranking influence.
8Robust Control Mechanisms
Multiple control layers ensured results validity. All sites were technically standardized beforehand. Schema additions/removals were performed by the same team. Data collection combined automated tools with manual checks. Search volume fluctuations were addressed using weekly averages. Geographic distribution balanced city/state profiles across groups. These controls created laboratory-like conditions rarely achievable in real-world SEO studies.
9Industry-Specific Advantages
Choosing the landscaping industry provided unique benefits. These businesses share remarkably similar services, target audiences and competition levels. All being local businesses eliminated national-scale variables. Evergrow's policy of building all client sites on the same WordPress theme ensured technical consistency. This homogeneous sample created a rare opportunity to measure schema's isolated effect without typical confounding factors plaguing SEO research.
10Comprehensive Data Analysis
Analysis focused on relative ranking changes rather than absolute positions. Keyword ranking movements were compared for each business. Differences between control and test groups underwent statistical significance testing. Seasonal search volume increases affected both groups equally. Mobile and desktop results were analyzed separately. Cross-search engine comparisons provided additional validation. This multidimensional approach yielded robust, actionable insights about schema's true impact.
11Strategic SEO Implications
The experiment provides clear answers about schema as a ranking factor. LocalBusiness schema showed measurable impact, particularly for local searches. However, its effect size must be weighed against other SEO factors. Cost-benefit analysis is crucial, especially for small businesses. Results also suggest different schema types may have varying impacts. The findings help SEO professionals make data-driven decisions about schema implementation priorities in their overall strategy.
12Future of SEO and Schema
This study offers significant evidence about schema's role in SEO. It provides insights into how Google utilizes schema markup. Results demonstrate that schema implementation represents a strategic decision for local businesses. However, schema isn't a magic solution - it works best combined with other SEO best practices. Future research should replicate this methodology across different industries and schema types. The experiment underscores the growing importance of data-driven decision making in SEO practices.
Original article: Moz Blog — Schema Markup'ın Arama Sonuçları Sıralamasına Etkisi