What is a triangle test
Simply put, a triangle test is a study in which you compare 3 samples and pick out the one that is different. Of the three samples, one is different while two are the same. If you can consistently pick out the different one, there is a pretty good chance that there is some difference that you’re picking up on. You might not always know what the difference is but sometimes that doesn’t matter. The key is that if you can notice a difference then there is probably something different about it.
When to conduct a triangle test
Triangle tests are useful whenever you need to determine whether a change in the formula is noticeable or not. So, they work well for…
- Fragrance evaluations – When you have an odour change and you want to see if there is a noticeable difference.
- New raw materials – To see if there is some performance effect by using a raw material
- Cost savings – Remove a raw material and see if anyone can tell a difference
- Formula development – See if changes you’ve made improve your results
The triangle test is one of the key tools that a cosmetic chemist has at their disposal.
A triangle test can be done by one person or by an entire panel of people. The former is best when making new prototypes and evaluating raw materials. The latter is better for making final decisions as it will give some statistics.
The first thing you to do is figure out what test you’ll run to compare the samples. For odour evaluations, this can be as simple as a “sniff test”. However, fragrance is more complex and one must learn how to “sniff” and to take into a consideration a variety of parameters and other techniques. Sniffing is not the best method!
Put the formulas in a small jars or bottles, label them and smell, touch or feel etc. Close your eyes for odour and texture and touch evaluations or with odour do it in a dark room so you can’t be influenced by colour. Colour in surroundings or on pack change perceptions.
You can use any number of tests such as foam tests, texture tests, moisturizing tests, touch tests, etc. It really depends on what you are testing and what characteristic you want to notice.
If you are doing a test in which you want to get some useful statistics, you need a panel of about 30 people before you get meaningful data. However, if the differences are significant decisions can be made on fewer subjects.
Ideally, if you are going to test the samples, you should have someone else make and fill the samples. At the very least you should have someone else fill and label them. That way you can be singly blinded and won’t be able to trick yourself.
Once you’ve tested the samples, it is helpful to re-run the test.
If the test was done with a panel of people you need to determine if there were statistically significant differences.