A/B testing
How to design experiments to evaluate the effect of improved navigation mental models on findability and user satisfaction.
In this evergreen guide, we explore rigorous experimental designs that isolate navigation mental model improvements, measure findability outcomes, and capture genuine user satisfaction across diverse tasks, devices, and contexts.
Published by
Dennis Carter
August 12, 2025 - 3 min Read
When planning experiments to test navigation improvements, begin by clarifying the causal question: does a redesigned information architecture, clearer labeling, or a more consistent interaction pattern actually help users locate items faster and with greater satisfaction? Start with a hypothesis that links mental model alignment to measurable outcomes such as time to find, path efficiency, error rates, and perceived ease. Define the user population, tasks, and environment to reflect real usage. Develop a base metric set, including objective performance metrics and subjective satisfaction scales. Pre-register the experimental protocol to promote transparency and reduce bias, and prepare a robust data collection plan that records context and user intent.
Designing the experiment requires a careful balance of control and ecological validity. Consider a randomized controlled trial where participants are assigned to a control version with existing navigation and a treatment version featuring the improved mental model cues. Use tasks that demand locate-or-identify actions across multiple categories, ensuring variability in item location and path length. Track metrics such as first-click success rate, dwell time on search results, and the number of backtrack events. Include qualitative probes after tasks to capture user rationale and satisfaction. Ensure that the test environment mimics real sites, with realistic content density and typical device use, to preserve applicability of findings.
Choose robust designs that manage bias and variability.
A well-formed hypothesis links cognitive alignment to observable behaviors. For example, you might hypothesize that an enhanced navigation model will reduce search time by a meaningful margin and raise satisfaction scores when users navigate to a requested item from category pages. Specify the primary outcome (time to locate) and secondary outcomes (search success rate, perceived usability, cognitive load). Predefine success criteria and thresholds that reflect practical improvements for product teams. Establish a data analysis plan that anticipates potential confounds, such as user familiarity with the site, task complexity, and device differences. This reduces the risk of ambiguous results and strengthens decision-making.
Selecting the right experimental design is essential to valid conclusions. A between-subjects design minimizes learning effects in a single session, but within-subjects designs offer greater sensitivity if you can mitigate carryover. Consider a mixed design that assigns participants to both conditions across separate sessions, counterbalancing order to control sequencing effects. Use adaptive task sequences to prevent predictability and to mirror real-world exploration. Include a clean baseline session to establish current performance levels. Additionally, incorporate a crossover or Latin square approach to balance task exposure. Use stratified sampling to ensure coverage of user segments with varying expertise and goals.
Build reliable measurement strategies for performance and satisfaction.
The selection of metrics anchors the experiment in actionable insights. Beyond raw speed, capture user satisfaction through standardized scales such as SUS or a tailored, task-specific questionnaire that probes perceived ease, confidence, and frustration. Include behavioral indicators like path efficiency, the number of tool uses, and success rates for locating items. Log contextual data such as device type, connection quality, and time of day to explain outcome heterogeneity. Consider a composite metric that combines performance and satisfaction, weighted according to strategic priorities. Predefine thresholds for success and communicate them to stakeholders so decisions are transparent and timely.
Data collection must be accurate, private, and analyzable. Implement event logging that precisely timestamps each interaction, including clicks, hovers, and scrolling, plus a clear record of the item located and its location path. Use calibrated response time measures to avoid conflating load delays with cognitive effort. Ensure participant consent and data anonymization procedures meet privacy standards. Establish data quality checks to identify and exclude anomalous sessions. Plan for missing data through appropriate imputation strategies or sensitivity analyses so the interpretation remains credible even when data is imperfect.
Employ rigorous pilots and transparent preregistration.
Pre-registration and documentation are your best defenses against bias. Before collecting data, write a protocol detailing hypotheses, sample size rationale, task sets, and analysis methods. Register primary and secondary outcomes, and declare any potential confounds you will monitor. Include a plan for intermediary analyses to detect early signals without peeking at results in ways that bias final conclusions. Transparency helps align team expectations, while pre-registered research strengthens credibility with stakeholders, privacy-minded participants, and external reviewers who may examine replication potential.
Pilot testing helps refine materials and metrics before full deployment. Run a small-scale version of the experiment to verify that tasks are solvable, instructions are clear, and interface changes behave as intended. Collect feedback on navigation cues, terminology, and layout, then iterate accordingly. Use pilot data to adjust the difficulty of tasks, the duration of sessions, and the reporting formats for results. Document lessons learned, revise the protocol, and confirm that the planned analyses remain appropriate given the actual data distribution and task performance observed in pilots.
Translate results into actionable, user-centered recommendations.
Analysis plans should be concrete and replicable. Compute primary effects with appropriate statistical models, such as mixed-effects regression for repeated measures or survival analysis for time-to-find data. Correct for multiple comparisons if you test several outcomes, and report effect sizes with confidence intervals. Explore interactions between user characteristics and the treatment to reveal who benefits most from the improved mental model. Use Bayesian analyses as a complementary check if prior information exists. Present results in a way that is accessible to product teams and comfortable for cross-functional discussion, highlighting practical implications rather than solely statistical significance.
Interpretation should link results to design implications and business value. Translate findings into concrete navigation changes, such as reorganized menus, consistent affordances, or targeted hint prompts. Identify scenarios where improvements did not materialize, and investigate potential explanations like task misalignment or cognitive overload. Propose actionable recommendations, including rollout plans, risk assessments, and metrics to monitor post-launch. Emphasize user-centered considerations such as accessibility and inclusivity to ensure the improved mental model benefits diverse users. Outline a plan for ongoing validation as content and structure evolve over time.
Consider scalability and variation across contexts. Your experiment should inform multiple product areas, from search to navigation menus and help centers. Plan for cross-platform consistency so that improvements in one channel do not degrade performance in another. Anticipate regional and language differences by including localized tasks and content. Evaluate long-term effects by running follow-up studies or longitudinal cohorts to assess retention of improved findability and satisfaction. Use dashboards to track key indicators, enabling product teams to monitor impact continuously. Ensure that insights remain adaptable as new features and data emerge, preserving relevance across iterations and releases.
Finally, document learnings and share insights widely. Create a concise executive summary that highlights the hypothesis, methods, outcomes, and recommended actions. Attach the full statistical analysis and data visuals for transparency, but provide digestible takeaways for stakeholders who may not be data experts. Encourage cross-functional discussions to translate findings into design decisions, engineering constraints, and customer support messaging. Schedule periodic reviews to reevaluate navigation models in light of user feedback and changing content. By closing the loop with practical, evidence-based changes, your team can continuously improve findability and satisfaction.
