Subject: "LLR with time"

Events have the natural good quality that having a cold start means that
you will naturally favor recent interactions simply because there won't be
any old interactions to deal with.

Unfortunately, that also means that you will likely be facing serious cold
start issues all the time. I have used two strategies to deal with cold
starts, both fairly successfully.

*Method 1: Second order recommendation*

For novel items with no history, you typically do have some kind of
information about the content. For an event, you may know the performer,
the organizer, the venue, possibly something about the content of the event
as well (especially for a tour event). As such, you can build a recommender
that recommends this secondary information and then do a search with
recommended secondary information to find events. This actually works
pretty well, at least for the domains where I have used (music and videos).
For instance, in music, you can easily recommend a new album based on the
artist (s) and track list.

The trick here is to determine when and how to blend in normal
recommendations. One way is query blending where you combine the second
order query with a normal recommendation query, but I think that a fair bit
of experimentation is warranted here.

*Method 2: What's new and what's trending*

It is always important to provide alternative avenues of information
gathering for recommendation. Especially for the user generated video case,
there was pretty high interest in the "What's new" and "What's hot" pages.
If you do a decent job of dithering here, you keep reasonably good content
on the what's new page longer than content that doesn't pull. That
maintains interest in the page. Similarly, you can have a bit of a lower
bar for new content to be classified as hot than established content. That
way you keep the page fresh (because new stuff appears transiently), but
you also have a fair bit of really good stuff as well. If done well, these
pages will provide enough interactions with new items so that they don't
start entirely cold. You may need to have genre specific or location
specific versions of these pages to avoid interesting content being
overwhelmed. You might also be able to spot content that has intense
interest from a sub-population as opposed to diffuse interest from a mass

You can also use novelty and trending boosts for content in the normal
recommendation engine. I have avoided this in the past because I felt it
was better to have specialized pages for what's new and hot rather than
because I had data saying it was bad to do. I have put a very weak
recommendation effect on the what's hot pages so that people tend to see
trending material that they like. That doesn't help on what's new pages for
obvious reasons unless you use a touch of second order recommendation.

On Sat, Nov 11, 2017 at 11:00 PM, Johannes Schulte <