Design Good Tests
Learn How To Be More Efficient In Your Testing, Bolster innovation And Design Good Tests That Follow Sensory Best Practices.
Sensory testing is a valuable risk management tool that can prevent companies from experiencing product disasters and help inform new product development. Sensory and consumer methodologies can be applied to achieve a myriad of objectives, including:
- Determining if a product has changed (discrimination)
- Measuring the sensory properties of products (descriptive analysis)
- Determining consumer responses to products (consumer research)
The test must be properly designed to obtain reliable and robust outcomes.
The Importance of Experimental Design
In sensory testing, the most common source of bias is the order effect. The first sample we see or taste is perceived differently because it’s a fresh experience. When we get the second sample, we have the first sample’s impact influencing our response.
The experimental design, that is the order of sample presentation, can be rotated and balanced to ensure that all samples are treated in the same manner and that the test is fair. If we insert a warm-up sample at the start of each sample set that is neither evaluated nor measured, then the effect is equal for all samples in the test.
Complete Block Designs
If we have too many samples to evaluate in one sitting, we can use sessions to manage our study. The large complete block design (CBD) can be sliced into columns and a limited number of columns may be presented in each sitting. This way the whole block can be evaluated over several days, or even weeks if the samples are sufficiently stable to permit doing so.
Balanced Incomplete Block Designs (BIB)
We can also opt for balanced incomplete block (BIB) designs that ensure that all samples are seen equally, but no one sees all the samples. The size of the block is based upon what an assessor can manage to evaluate in one session without compromising data quality by fatigue or carry-over. It is possible to balance blocks over sessions to have all samples seen by each panelist.
Sensory Informed Designs (SID)
This BIB technique begins with determining the sensory profiles of the products through descriptive analysis. We ensure that the products chosen cover the sensory space, the range of attributes and their intensities, of the product category. The incomplete blocks are made using products that have a sensory contrast and can be used to cluster our consumers on their liking response.
Out of 16 possible products, consumers have only conducted SID category appraisals on 6. This approach cuts the cost of these studies in half and delivers excellent products development guidance.