What are two ways you can improve the validity of an experiment?
Validity of an experiment certifies its fairness. The factors that could affect the validity of a test are represented by the followings: appropriate measuring tools and equipment, the variables that are measured, the established range of values. There exists two types of validity, internal and external.
There are many means to check the internal validity of an experiment, such as predictive, concurrent and face validity.
Predictive validity shows if a new measure can forecast the future results. Face validity indicate if the measurement is appropriate and suitable for what is intended to measure. Concurrent validity indicates if the results of a new experiment are comparable to the results obtained by performing other experiment, in the same field.
Improvements to internal validity are brought by means of investigations using single- or double-blind study techniques.
There are also several means to check the external validity of an experiment, such as ecological, historic and population validity. The improvements to external validity are brought about by means of investigations using diverse samples. The more diverse the sample used are, the more applicable to a wider population the results will be.
There are far more than two ways to improve the validity of an experiment, depending on the data gathered thus far and the factors involved in the experimental design, but here are two things for you to remember.
First, there's a reason we call it "RE-search." Repetition will improve validity, because when you've gathered data repeatedly and observed similar results over time using the same methodology, you are working toward proving your hypothesis or, perhaps, reproducing results that have been previously observed. Repetition will also increase your sample size, which may lower P values and statistically show that your experiments are exhibiting data that are likely true.
Second, focus on control. The control you maintain over the measured variables of the experiment (time, temperature, age, volume, etc.) is key for producing sound data. You'll also control the amount of error introduced by you or the instruments you use. Most importantly, you should always check the controls you use in the experiment and alter them or add more accordingly. This is all paramount to designing experiments with integrity, which ultimately should lead to valid data that are reproducible and believable, supporting your hypothesis and the scientific method you used.
Three simple ways to improve the validity of an experiment:
1. Change only one independent variable at a time.
2. Measure dependent (responding) variable accurately.
3. Did you keep all other variables constant, were there variables like wind speed that you could not control and didn't measure that impacted your results?