THAT'S THE JOB OF THE SCIENTIFIC METHOD
That's the job of the scientific method. It provides an objective, standardized approach to conducting experiments and, in doing so, improves their results. By using a standardized approach in their investigations, scientists can feel confident that they will stick to the facts and limit the influence of personal, preconceived notions.
Even with such a rigorous methodology in place , some scientists still make mistakes. For example, they can mistake a hypothesis for an explanation of a phenomenon without performing experiments.