Presenting consumers with irrelevant or poor recommendations on travel websites is likely to be more damaging to a brand than in other retail sectors.
Professor Barry Smyth, digital chairman of computer science at University College Dublin, said firms were better off providing no recommendations at all than poor ones.
“Recommender systems are easy in a sense,” he said.
“It’s easy to start generating but difficult to generate good ones.
“The missing ingredient is domain knowledge, your understanding of what works in your particular market and what consumers are looking for.”
Smyth said travel differed from other sectors because the product was not “atomic” and needed to be combined with other components to create a meaningful package.
This meant the potential number of products expanded exponentially, so it was important that alternatives offered were personalised to the consumer.
“There’s a whole range of components that make up a good travel recommendation and you cannot pick those in isolation,” he said.
“As a consumer you are likely to be far more tolerant of miss-recommendations when browsing for books, music or DVDs.
“I think that’s unlikely to be the case when you are focused on building the perfect trip for your family holiday.
“You will find your consumers will not be tolerant of being suggested irrelevant recommendations merely because there’s some correlation between some people’s past purchases.”
Smyth said travel had always been a “gnarly” problem for recommendation engines but that in terms of the volume of academic research it was third behind movies and music.
“Travel is one area that’s growing most,” he said. “That tells us there is a lot of pent-up research and ideas around about how to apply recommender systems in travel.”
Smyth said there had been a move toward using social recommendations with online film service Netflix a prime example, but also Booking.com in travel, which asks users to rate reviews, and TripAdvisor, which has integrated with Facebook.