Describe a time when you encountered a problem during an experiment. How did you troubleshoot and resolve the issue?

Sample answer to the question

During a recent experiment I conducted, I encountered a problem when the data I collected seemed inconsistent with my initial hypothesis. To troubleshoot the issue, I carefully examined my experimental setup, checking all the equipment and ensuring they were calibrated properly. I also reviewed my methodology and experimental design to identify any potential flaws. After analyzing the data more closely, I discovered that there was an error in one of the calculations I had made, which was causing the inconsistencies. I immediately corrected the error and reanalyzed the data. The results aligned more closely with my hypothesis, confirming that the initial problem was due to the calculation error. To prevent similar issues in the future, I implemented a double-checking system for all calculations and collaborated with a colleague to review and verify each other's work.

A more solid answer

During one of my experiments, I encountered a problem when the data I obtained from a specific sample did not align with the expected results. To troubleshoot the issue, I first checked the equipment to ensure it was functioning properly and calibrated correctly. When I noticed no issues with the equipment, I analyzed the experimental conditions and methodology for any potential flaws. While reviewing my lab notebook, I realized that I had accidentally used the wrong reagent concentration for that particular sample. This error could have skewed the results. To resolve the issue, I repeated the experiment with the correct reagent concentration and obtained consistent and expected results. To prevent similar mistakes in the future, I implemented a thorough review process, where I cross-checked all reagent concentrations with a colleague before conducting any experiment. This collaborative approach not only helped identify potential errors but also fostered a culture of open communication and knowledge sharing within the lab.

Why this is a more solid answer:

The solid answer expands on the basic answer by providing more details about the problem encountered. The candidate mentions checking the equipment and analyzing the experimental conditions and methodology. They also highlight the important step of reviewing their lab notebook to identify the specific error that caused the problem. The candidate also mentions how they resolved the issue by repeating the experiment with the correct reagent concentration. Additionally, they describe the implementation of a review process with a colleague to prevent similar mistakes in the future, highlighting their ability to work collaboratively.

An exceptional answer

During a critical experiment, I encountered a problem when the data I collected showed significant deviations from the expected trends. To troubleshoot the issue, I conducted a step-by-step analysis of every aspect of the experiment, starting with the sample preparation. I discovered that a small contamination in one of the reagents was responsible for the unusual results. To confirm this, I performed additional tests and observed the same deviations when using the contaminated reagent. To resolve the issue, I immediately ordered a new batch of reagents and repeated the experiment. The results were consistent with the expected trends, confirming the contamination as the cause of the problem. To prevent similar issues in the future, I implemented a rigorous quality control system for all reagents, including regular testing and monitoring. I also actively collaborated with the lab technician to ensure proper storage and handling of reagents. These measures significantly reduced the occurrence of experimental errors and improved the reliability and reproducibility of our results.

Why this is an exceptional answer:

The exceptional answer surpasses the solid answer by providing even more specific details about the problem encountered. The candidate conducts a comprehensive analysis of every aspect of the experiment, including sample preparation, and identifies a small contamination in one of the reagents as the cause of the problem. They emphasize their dedication to confirming this cause by performing additional tests. The candidate also takes proactive steps to prevent future issues by implementing a rigorous quality control system and collaborating closely with the lab technician. These measures demonstrate their strong analytical and problem-solving capabilities, as well as their commitment to maintaining high standards in the laboratory.

How to prepare for this question

Review your past experiments and identify instances where you encountered problems. Practice explaining the problem, your troubleshooting process, and how you resolved it.
Familiarize yourself with common issues and challenges in experimental work, such as equipment malfunctions, human errors, and sample contamination. Research troubleshooting strategies for these problems.
Highlight your ability to analyze and interpret data. Share examples where you identified patterns or inconsistencies in experimental data and explain how you addressed them.
Demonstrate your collaboration skills by discussing instances where you sought help or advice from colleagues to troubleshoot and resolve experimental issues.
Prepare concrete examples of how you implemented quality control measures in the lab to ensure reliable and reproducible results.
Practice conveying your problem-solving mindset and ability to stay calm and focused when faced with unexpected challenges in the lab.

What interviewers are evaluating

Analytical and problem-solving capabilities
Experience with troubleshooting experiments
Ability to work collaboratively in a multidisciplinary environment