How to assess numerical reasoning in an interview

Imagine a candidate with a stellar resume joining your team. However, once established, you realize they struggle with practical numerical challenges like financial analysis, budgeting, and market trend interpretation. You find your business affected by data analysis issues, missed opportunities for informed decisions, and reduced team efficiency.

Sadly, it's a scenario that many employers have faced.

To steer clear of these situations and prevent mis-hiring, it's vital to gauge candidates' numerical reasoning skills during the interview stage. However, traditional interview questions don't always uncover how candidates handle real-world numerical scenarios.

This guide offers strategies for assessing numerical reasoning skills during interviews, ensuring that you can identify candidates who’ll excel in handling numerical challenges on the job.

What you need to know about numerical reasoning 

Understanding numerical reasoning is crucial for effective workplace performance. The skills involved include the ability to interpret, analyze, and draw conclusions from numerical data. Here's a general overview of what it comprises: 

• Basic arithmetic: This includes addition, subtraction, multiplication, and division, fundamental for everyday calculations and understanding data.

• Data interpretation: Understanding graphs, charts, and tables to extract meaningful insights and make informed decisions.

• Problem-solving: The ability to apply numerical reasoning to solve work-related problems, often involving logical thinking and analytical skills.

• Statistical knowledge: Understanding statistical methods and results, which is vital for interpreting surveys or research data.

• Budget management: This is crucial in roles involving financial planning, where understanding and managing numerical data is key.

Roles where numerical reasoning skills are particularly important include:

• Financial analysis: Interpreting and analyzing numerical data to make financial predictions and decisions.

• Engineering: Designing, analyzing, and troubleshooting technical projects.

• Healthcare: Numerical reasoning is used for medication dosages and interpreting patient data.

• Marketing analysis: Using data trends to inform marketing strategies and decisions.

• Retail: Inventory management, sales analysis, and budgeting.

Numerical reasoning skills are essential for data-driven decision-making, effective problem-solving, and accuracy in roles across various industries.

How to assess candidates’ numerical reasoning skills during interviews 

In this section, we explore the interview questions, observations, and technology to accurately assess numerical reasoning efficiently.

Interview questions you can ask to assess numerical reasoning skills 

General numerical reasoning 

This category assesses basic mathematical understanding and the ability to perform calculations. Below, you'll find examples for each question to see how well a candidate can use basic number skills in everyday tasks.

• Basic calculations: “How would you calculate a 15% increase in our sales from last year?” This tests basic arithmetic and percentage skills.

• Data analysis: “Given a set of sales figures, can you identify trends or key insights?” This assesses their ability to interpret and analyze data.

• Ratio and proportions: “How would you use ratios to compare the performance of two products?” This evaluates their understanding of ratios in practical situations.

• Estimations: “If our website traffic increases by 20% monthly, estimate our visitor count in six months.” This tests their ability to make quick and accurate estimations.

Situational interviews

Situational interview questions assess a candidate’s ability to apply numerical reasoning in specific job-related scenarios. 

Below, we provide some example questions to help gauge candidates’ practical application of numerical skills and decision-making abilities in the workplace. 

• Budgeting scenario: “Imagine you have a limited budget for a project. How would you allocate the funds and why?” This evaluates practical applications in budgeting.

• Statistical problem: “You’re presented with conflicting statistical data on a report. How would you determine which data to trust?” This tests critical analysis with numbers.

• Cost analysis: “Explain how you would assess the cost-effectiveness of two different vendors.” This question gauges understanding of factors affecting cost.

• Risk assessment: “Describe how you would use numerical data to evaluate the risk of a new investment.” This assesses the candidate’s ability to use numbers for risk evaluation.

Behavioral interviews

Behavioral interviews delve into a candidate's past experiences and actions. They specifically focus on how candidates have previously used their numerical skills. This approach helps forecast their future behavior and performance in similar scenarios.

• Past experience: “Describe a time when you used numerical data to make a significant decision. What was the outcome?” This explores real-life applications.

• Handling errors: “Tell me about a time when you found an error in your numerical analysis. How did you handle it?” This reveals the candidate’s approach to accuracy.

• Team collaboration: “Can you give an example of how you have used numerical reasoning to contribute to a team project?” This assesses teamwork and data use.

• Overcoming challenges: “Share an instance where you had to make a quick numerical decision under pressure. What was the situation and result?” This explores the ability to use numerical reasoning in challenging situations.

These questions will effectively measure a candidate’s numerical reasoning skills from basic competency to practical application and past behavior, giving a well-rounded view of their abilities.

Observations you can make 

To effectively assess numerical reasoning skills in your interviews, it's crucial to observe how candidates handle various question types, including those about behavior, situational challenges, and basic numerical reasoning. 

This approach allows you to measure not only their numerical skills but also their problem-solving methods and adaptability.

As candidates respond to your numerical reasoning questions, pay close attention to the following key factors for a comprehensive assessment:

• Analytical thinking: Observe how candidates approach and solve numerical problems. Are they methodical and logical in their process?

• Accuracy and attention to detail: Check for accuracy in their calculations and their attention to detail with data.

• Time management: Notice how quickly and efficiently they can handle numerical questions, which is crucial in time-sensitive decision-making scenarios.

• Adaptability in problem-solving: Evaluate how candidates adjust their approach when faced with unexpected or complex numerical challenges. Do they remain flexible and find effective solutions?

• Communication of numerical information: Pay attention to how candidates explain their numerical reasoning and conclusions. Are they clear and concise in communicating complex data?

• Critical thinking: Assess how candidates interpret data and numbers beyond surface-level analysis. Do they demonstrate the ability to think critically and draw insightful conclusions from numerical information?

Technology you can use 

Before formal face-to-face interviews, consider pre-assessing candidates using numerical reasoning tests available on talent assessment platforms like TestGorilla. 

Tests are designed to objectively evaluate a candidate's numerical abilities, providing a fair and data-backed assessment. This approach ensures that only those with proven numerical skills are selected for the next stage of the interview process.

Here are some specific tests to get you started: 

• Numerical Reasoning test: Evaluates candidates' overall ability with numbers and their capability to interpret numerical data for various purposes. It's designed to help you pinpoint candidates who excel in numerical skills.

• Statistics and Probability test: Measures candidates' grasp of essential concepts in statistical data analysis, aimed at identifying those capable of performing statistical evaluations of your data.

• Intermediate Math test: Measures candidates' proficiency in solving mathematical equations and problems that include fractions, decimals, percentages, ratios, and time calculations. It identifies candidates who are adept at working with numbers.

• Working with Data test: Assesses candidates' skills in data handling and basic analysis, helping you find those proficient in using data to track and present results.

By adding these tests and observations to your interview process, you can get a detailed understanding of a candidate's skills with numbers. This ensures they're equipped for jobs that demand strong numerical reasoning.

Common mistakes when assessing numerical reasoning skills 

Avoid these pitfalls when assessing your candidates’ numerical reasoning skills.

Conducting unstructured interviews 

Unstructured interviews can cause unintentional bias, based on an assessor’s preferences or interpretation of responses. Questions often lack consistency, which can make objective comparisons challenging. This can lead to selecting candidates who interview well but lack the required numerical skills or vice versa.

To mitigate these issues, use structured interviews and standardized assessments, where all candidates are asked the same questions. This approach, applicable in both in-person and one-way video interview formats, provides a more objective evaluation of a candidate's numerical reasoning skills, ensuring a fairer and more accurate selection process.

Neglecting complementary skills

In interviews, avoid overlooking soft skills while assessing numerical abilities. For instance, though a candidate might be skilled at crunching numbers, it's equally important to see if they can explain their findings clearly or work well in a team. 

Interviews should also measure critical thinking and problem-solving skills, as these often complement numerical reasoning. Focusing only on numerical tests and related questions might cause you to miss out on candidates who are great at turning data into actionable strategies or collaborating with others to solve complex problems. 

An effective interview process should include scenarios or questions that reveal these broader skills, ensuring a well-rounded evaluation of each candidate's potential.

Hire strong numerical reasoners with TestGorilla 

In the interview, picking a candidate with strong number skills means more than just finding a math expert. It's about selecting someone who can help with data analysis and smart decision-making.

Not paying attention to these details during the interview can lead to problems with analysis, missed opportunities, and less effective use of data.

TestGorilla offers a range of online tests and interview questions to identify candidates with strong numerical reasoning skills. From math skills tests to behavioral interviews, we provide all the tools you need to efficiently identify the ideal candidate for roles demanding numerical proficiency.

Start your hiring process today with a free account, live demo, or product tour to discover the full scope of TestGorilla's capabilities.