Split-ballot design is a valuable technique employed in survey research to reduce bias and increase the validity of survey results. It involves dividing the survey sample into multiple groups and presenting each group with different versions of the survey questionnaire. 

This approach allows you to explore the impact of variations in question formats, stimuli, or other experimental conditions on participant responses. In this article, we will delve into the concept of split-ballot design, its applications, and its pros and cons. We will also provide a comprehensive understanding of this vital survey research technique.

Understanding Split-Ballot Design

Split-ballot design refers to the practice of creating multiple versions of a survey questionnaire and randomly assigning participants to one of the different versions. The purpose of employing a split-ballot design is to examine how variations in the survey instrument affect participant responses. Thereby allowing you and other researchers to explore potential biases and increase the validity of your findings.

For example, you may present one group of participants with a question using a Likert scale, while another group receives the same question with a semantic differential scale. When you compare the responses between these groups, you can gain insights into how the choice of question format influences participant perceptions and preferences.

Split-ballot designs offer flexibility in the types of variations that can be introduced. These variations can include alterations in question-wording, response options, question order, or the inclusion of different stimuli. For instance, you can present participants with different versions of an advertisement. This can include an image, or video to explore how these stimuli affect attitudes, perceptions, or behavioral intentions.

Employing split-ballot designs can help you uncover potential sources of bias in your survey research. Additionally, split-ballot designs enable you to assess the robustness and generalization of your results, as you can explore the consistency or variation of findings across different experimental conditions.

Advantages of Split-Ballot Design

Split-ballot designs offer several advantages and benefits in survey research. Here are some key advantages:

  • Control for response bias and order effects: Split-ballot designs allow researchers to control for response bias and order effects. By randomly assigning participants to different versions of the survey questionnaire, the impact of response biases, such as acquiescence bias or primacy/recency effects, can be assessed. This helps to minimize the influence of these biases on the overall results, leading to more accurate and reliable findings.
  • Compare and contrast effects of different variables or conditions: The designs enable researchers to compare and contrast the effects of different variables or experimental conditions. For example, you can examine the impact of different pricing options, product features, or advertising messages by presenting different versions of the survey to different groups. This allows for a direct comparison of participant responses under varying conditions, providing valuable insights into the factors that drive preferences or behaviors.
  • Enhance validity and generalizability: When you explore the impact of different survey designs or experimental conditions, split-ballot designs help you increase the validity and generalizability of survey findings. Researchers can identify design choices or variations that may introduce bias or affect responses, allowing for adjustments and improvements to enhance the overall validity and reliability of the survey instrument. Additionally, assessing the consistency or variation of findings across different experimental conditions provides a more comprehensive understanding of the phenomenon under investigation.

Implementing Split-Ballot Design

Implementing a split-ballot design requires careful planning and consideration. Here are some key steps involved:

  1. Define research objectives and variations: Clearly define the research objectives and identify the specific variations or conditions to be tested in the split-ballot design. This could include variations in question-wording, response options, stimuli, or experimental conditions.
  2. Randomly assign participants: Randomly assign participants to different versions of the survey questionnaire to ensure unbiased representation. Randomization will help you to minimize selection bias and ensures that each participant has an equal chance of being assigned to any particular version.
  3. Consider sample size and statistical power: Adequate sample sizes are essential to ensure sufficient statistical power and validity of the findings. Consider the desired effect size, significance level, and statistical power calculations when determining the sample size for each group. Larger sample sizes provide greater precision and increase the reliability of the results.
  4. Implement consistent data collection procedures: Use standardized data collection procedures across all versions of the survey to maintain consistency. Ensure that the administration of the survey, instructions provided to participants, and data collection protocols are the same across all groups. This will help you to minimize potential confounding factors.
  5. Analyze and compare results: Analyze the data collected from each version of the survey questionnaire and compare the results across the different groups. Use appropriate statistical techniques, such as hypothesis testing or regression analysis, to assess the effects of the variations on participant responses.
  6. Interpret and report findings: Interpret the findings of the split-ballot design, considering the impact of the variations on the survey results. Discuss the implications of the findings, including any significant differences observed between the groups. You must report the split-ballot design and its implementation details transparently to allow for replication and to enhance the credibility of the study.


Examples and Applications of Split-Ballot Design

Split-ballot designs have been widely used in various research domains to investigate the impact of variations on survey responses. Here are some examples of split-ballot designs in different fields:

  1. Political polling: In political polling, split-ballot designs are often employed to test the effectiveness of different campaign messages or candidate attributes. Different versions of the survey may present respondents with varying descriptions of candidates’ qualifications, issue positions, or personal backgrounds. When you compare the responses across different groups, you can gain insights into the effects of these variations on voter preferences and decision-making.
  2. Product testing: Split-ballot designs are frequently utilized in product testing to assess consumer preferences and choices. For instance, participants may be presented with different versions of product packaging, pricing options, or product descriptions. This will help you determine which variations have a significant impact on consumer behavior. You can also use this to make decisions about marketing strategies or product development.
  3. Social studies: In social studies, split-ballot designs are valuable for examining public opinion on controversial issues or policy options. Different versions of the survey may present respondents with different arguments or policy proposals. Compare the responses to gain insights into how variations in framing or presentation affect public attitudes and preferences. This will also inform your policy development and decision-making.


These examples of split-ballot designs have provided valuable outcomes and insights. Researchers have identified specific messages, attributes, or factors that significantly influence voter preferences, consumer choices, or public opinion. 

Such findings have informed political campaign strategies, marketing campaigns, and policy development, enabling decision-makers to tailor their approaches and communications to better align with target audiences.


Challenges and Limitations of Split-Ballot Design

While split-ballot designs offer numerous benefits, there are several challenges and limitations to consider:

  1. Participant fatigue: Respondents may experience fatigue or frustration when exposed to lengthy or repetitive surveys, potentially affecting their responses. To mitigate this, researchers should carefully design surveys that are concise and engaging, reducing the risk of participant fatigue.
  2. Response bias: Even with random assignment, there is still a possibility of response bias due to individual differences or uncontrolled factors. You should be cautious in interpreting and generalizing the results, considering the potential for bias introduced by participants’ characteristics or attitudes.
  3. Potential confounding factors: Split-ballot designs aim to isolate the effects of specific variations; however, other factors may confound the results. You should carefully account for potential confounding variables and consider additional statistical techniques, such as covariate adjustment or matching, to control for these factors.
  4. Interpretation and consideration of results: Careful interpretation of the results is essential, considering the context and limitations of the split-ballot design. Researchers should acknowledge the potential impact of variations and provide a balanced interpretation of the findings, recognizing the complexity of human behavior and the multiple factors that influence responses. 



In conclusion, split-ballot design is a valuable technique in survey research that allows researchers to explore the impact of variations in question formats, stimuli, or other experimental conditions on participant responses. Researchers must carefully plan and manage the data collection process to ensure accuracy, reliability, and proper allocation of participants to each version.

When you employ this design, you can reduce bias, increase validity, and gain insights into the factors that influence survey results. While split-ballot designs offer numerous advantages, careful planning, and implementation are necessary to address potential challenges and ensure accurate data collection and analysis.

  • Emmanuel
  • on 7 min read


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