blind test

Từ điển Oxford Advanced Learner 8th

ˌblind ˈtest 7 [blind test] BrE NAmE noun
a way of deciding which product out of a number of competing products is the best or most popular, or how a new product compares with others. People are asked to try the different products and to say which ones they prefer, but they are not told the names of the products
•In blind tests, consumers chose our cola over more established brands.