Publish Time: 2025-07-10 Origin: Site
'Repeat at least three times' is the basic criterion for repeating scientific research experiments. It is based on experimental errors, statistical laws and scientific research verification mechanisms, and is an important scientific norm to ensure research quality.
1. The core reason why experiments need to be repeated
The limitations of a single experiment include two types of unavoidable errors:
①Systematic error:
Due to experimental design flaws, operational deviations, etc., such as instrument calibration misalignment and environmental parameter out-of-control, the experimental results may not be reproducible.
②Random error:
Microscopic uncontrollable factors, such as pipetting shake and individual differences in cells, are sporadic and unpredictable, which will expand the confidence interval of the results.
2. 'Repeat at least three times' basis
When repeated three times, according to the binomial distribution, the probability of being closer to the true value reaches 75%, which can initially reflect the law of large numbers. The error range can be determined by calculating the average and standard deviation, which cannot be achieved in a single experiment.
3. The error between two repetitions is large and it is difficult to show the authenticity.
Eliminate accidental events: Abnormal results can be found by repeating multiple times (such as a difference of more than 20% between one time and the other two), and the troubleshooting process can be started to avoid interference from accidental factors (such as false positives caused by cell contamination).
①Look for repeatable patterns
The trend consistency can be observed in the three results (for example, group A is always higher than group B and the difference is reasonable), but the two times may not form a valid conclusion due to coincidence.
②Resist academic fraud
The three results of real experiments usually fluctuate by 5%-10%. Standard recording of raw data (including outliers) can serve as the lowest line of defense for scientific research ethics.
4. Need to increase the number of repetitions
High variability experiments (such as animal experiments): usually 5-10 times.
Accurate measurement requirements (such as drug LD50 determination): more than 20 times.
New method establishment: at least 10 times to demonstrate stability.
5. Core conclusion
Three repetitions are the basis for the experiment to move from 'accidental' to 'inevitable' and are the basic principles for controlling errors, verifying rules, and adhering to ethics in scientific research. Scenarios with higher requirements require further increase in the number of repetitions.
At the same time, the selection of consumables is also very important. With its profound insight into the needs of scientific research, Aijin Biotechnology has developed many practical and efficient experimental consumables, such as deep well plates, pipette tips, cell culture dishes, centrifuge tubes, etc., which are highly favored in the field of scientific research.