Table A1.

Hyperparameter values for collaborative KNN recommender algorithms on all datasets.

Algorithm	Hyperparameter	ContentWise Impressions	Netflix Prize	Movielens 20M
UserKNN CF	topK	297	1000	835
	shrink	102	0	0
	similarity	cosine	cosine	cosine
	normalize	True	True	True
	feature weighting	TF-IDF	none	none
ItemKNN CF	topK	5	72	214
	shrink	0	0	982
	similarity	cosine	cosine	cosine
	normalize	True	True	True
	feature weighting	none	TF-IDF	none