Implementing a method that reduces random errors will improve reliability. The reliability of single measurements is not improved through repetition, but through the design of the experiment. Improving reliability is a different matter to testing it. However, repetition alone doesn’t make your measurements reliable, it just allows you to check whether or not they are reliable. The more similar repeated measurements are, the more reliable the results.
You can test reliability through repetition.
#Differentiate between validity and reliability how to
How to you improve reliability?Ī measurement is reliable if you repeat it and get the same or a similar answer over and over again, and an experiment is reliable if it gives the same result when you repeat the entire experiment. You can consider the reliability of a measurement, or of the entire experiment. Reliability is about how close repeated measurements are to each other.
If this assumption is not satisfied, then the experiment will be invalid. This equation assumes there is no flux leakage, so suitable equipment such as a ferromagnetic core must be used. If your experiment is invalid, then the result is meaningless because either the equipment, method or analysis were not appropriate for addressing the aim.Īn example from Module 6 Electromagnetism, is an experiment involving transformers, using the transformer equation: \(\frac \). You may be able to identify invalid measurements and discard them from the analysis. The experimental method must ensure that all the assumptions are satisfied, otherwise, you will end up using a method or analysis that is inappropriate, and the result will be invalid. maybe something has been simplified, or an equation being used is an approximation. The method (including the analysis) may contain some assumptions that need to be satisfied, e.g. This forms part of the experimental method. All other variables are called control variables, and they must be kept constant to prevent them from affecting the dependent variable. The dependent variable is the one you measure (Y, because it depends on X). The independent variable in an experiment is the one you set (X). The correct way to describe this is in terms of the independent, dependent, and control variables. To address this, you must only change X, and see what happens to Y. If you allow other changes at the same time, then you cannot make a valid conclusion about how X affected Y, since Y may have been affected by the other changes as well. The experiment is ultimately testing a relationship between cause and effect: how changing X affects Y. 
The equipment must be suitable for carrying out the experiment and taking the necessary measurements. Several aspects of the experiment can contribute to validity: the equipment, the experimental method, and the analysis of the results.Īlthough it may seem obvious, the appropriate equipment needs to be used.
“Am I actually measuring what I’m trying to measure?”. “Does it test what it’s meant to test?” or. Validity relates to the experimental method and how appropriate it is in addressing the aim of the experiment: When writing the method of an experiment, you must ensure that each step of the method incorporates reliability, accuracy or validity. Relationship between reliability and accuracyĪn experiment is a set of measurements that are analysed to test a link or relationship between different things. The measurements are usually analysed in an experimental report, which is set out in a clear format to help the reader understand different aspects of the experiment, like the aim, the equipment and method used, the results obtained, how they were analysed, and what conclusions can be drawn. So what do these terms mean and how do these things affect each other? In this article we discuss: One aspect of this is the reliability, validity, and accuracy of the experiment. Practical assessments are designed to test your practical skills: how well you can design and carry out an experiment and analyse results, but also your understanding of the purpose of the experiment and its limitations. Introduction to Validity, Reliability, and Accuracy of Experiments
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