“…Validation data sets in addition to the expected training and testing sets were used in 5% of studies. 12 , 32 , 41 , 72 Another 7 studies trained their models with cross-validation on one data set and tested their method on an external, independent data set. 23 , 29 , 45 , 59 , 61 , 66 , 73 Crohn’s disease data (only) was used in 27 studies, 12 , 17 , 19 , 26–29 , 32 , 37–39 , 41 , 44 , 47–50 , 58 , 60 , 63 , 65 , 74–79 and UC data (only) was used in 15 studies, 25 , 40 , 42 , 46 , 52 , 55 , 59 , 61 , 62 , 64 , 68–70 , 80 , 81 with the remainder ( n = 36) using a mix of CD and UC data, or IBD data as one class.…”