Design
A well-designed experiment is more likely to yield meaningful results while minimising the risk of unforeseen errors! The following article aims at giving you an overview over useful strategies and tools for designing your experiments.
If you are planning to conduct experiments in UUBF's facilities, please read through our important information.
Experimental design - The backbone of all experiments
Before you start your experiments, it is advisable, that you spend a sufficient amount of time designing your experiments. A good study design will help to reduce errors as well as being easier to replicate and yielding more consistent results. In addition to this, a well-designed experiment may reduce the number of animals needed to achieve meaningful results. For more information on how to optimize the use of animals in your experiments, please consult our page regarding the 3Rs.
The information provided here is not meant to be a comprehensive summary of all steps required for planning and designing experiments. Instead, it aims at helping you consider some vital points of a study during the design process. Please refer to the PREPARE guidelines for planning animal research and testing when designing and planning experiments.
2. Choose which model organism to use for your experiments
The choice of your model organism will greatly influence the design of your study. If you are unsure about the choice, feel free to write an email to UUBF for a consultation.
3. Choose an appropriate test for your hypothesis
Once you have chosen one or more model organisms for your study, select the appropriate tests to answer your research question. UUBF offers a variety of different tests for mice, rats and fish. You can check which types of tests are available at UUBF in our lists of available tests. If you cannot find the test you were looking for, email UUBF and describe what you are looking for.
4. Determine the groups needed for the experiment
In this step, you will have to decide what type of groups you will need. This choice depends largely on your hypothesis. Keep in mind that the number of groups will directly effect following choices such as statistics, sample size and data analysis. It might be a good idea to revisit this step if you later find that, for example, your required sample size is too large.
5. Make a draft for data analysis and statistical tests
By now, you will have a good grasp of the data you will gain from your experiments and the parameters you want to analyse. Based on this information, the needed steps of data preprocessing as well as statistical analysis will be apparent. By drafting a plan for data analysis and statistical testing already before starting your experiments, you can make sure that you will:
- Gather exactly the data you will need to perform appropriate testing
- Streamline your data analysis and
- Avoid compromising your statistical testing, as you are only performing one, appropriate test.
6. Determine the sample size needed to achieve meaningful results
There are several ways to plan the sample size you will need for your experiments. We recommend that you perform a power analysis based on your selection of experimental groups and statistical tests. You can find a list of online tests and the corresponding R code to implement the tests yourself on the following webpage
If this results in a very large sample size, you now have the opportunity to adjust your experimental setup or groups.
Conducting a pilot experiment can help to determine your needed sample size. Please notice that you need to have ethical approval for conducting pilot experiments (see paragraph 8).
For more information regarding power and sample size, please consult the NC3R article on the topic.
7. Contact veterinarian and facility staff
Once your have a clear experimental plan, discuss the procedures with the responsible veterinarian and your facility staff. This gives you the opportunity to improve your design, find pitfalls and prepare for your ethical application.
8. Write up experimental plan and send in ethical application
After discussing and, if necessary, revising your experimental plan, write up the final version. Then, submit an ethical application for your planned experiments.
Designing experiments using the Experimental Design Assistant
The British NC3R provides a tool that can assist you in designing experiments, the Experimental Design Assistant (EDA). The tool allows you to create an experimental scheme including the creation of groups and consideration of interfering variables. You can furthermore enter your independent variables and measured values as well as data transformations. Based on this information, you can then use the EDA to get suggestions on statistical tests suitable for your experimental design.
After entering all appropriate information in EDA, you can generate a report with suggestions for improvements of your experimental design.
When using the EDA, you can either use it as a simple sketching tool for experimental processes or for more in-depth designing. Getting used to some of the more in-depth aspects will, however, require some time. In addition, the quality of the suggestions will largely depend on the amount of information you provide the EDA.
UUBF support - from design to published paper
The backbone of all experiments
A well-designed experiment is more likely to yield meaningful results while minimising the risk of unforeseen errors.
From design to result
Put your plans in practice using UUBF's facilities, equipment and expertise.
Gain insights
Get the most out of your data by optimising your data analysis.
Report your findings
Provide the most value to the scientific community by publishing your results in a clear and concise way.
