topic Re: Movie recommendation engine in QlikView

Movie recommendation engine

Mon, 03 Mar 2014 14:51:56 GMT

Dear all,

I have a database full of users and which movies they watched. Now I would like to make a simple recommendation. For example: people who viewed Movie A also watched Movie B.

I have no idea where to start and also no idea how to formulate my question correctly to be able to search this forum.

All help is greatly appreciated.

Best regards,

Dorine

Re: Movie recommendation engine

Mon, 03 Mar 2014 18:13:17 GMT

Maybe some more info is handy:

In the database is information stored about the viewer (name, gender, date of birth) as well as the movie (title)
I would like to be able to select Movie A and then see what other movies have been watched by people who have watched Movie A. Preferably I would like to rank the other movies on number of views.

Hopefully this explains a little bit better what I am trying to achieve. All advice is welcome!

Re: Movie recommendation engine

Luis_Cortizo — Mon, 03 Mar 2014 19:07:35 GMT

Sounds to me like a Basket Analysis problem. There are some examples on the community:

Re: Check if two certain products are sold together ?

Expression to know the mix product

but for this specific question:

I would like to be able to select Movie A and then see what other movies have been watched by people who have watched Movie A. Preferably I would like to rank the other movies on number of views.

That's almost the definitio of a P function. You want to return the movies that have been seen by the people that have seen Movie A.

If you take a look at the last part of the Set Analysis help in QlikView you can find examples, for instance:

sum( {$<Customer = P({1<Product={‘Shoe’}>} Customer)>} Sales )

returns the sales for current selection, but only those customers that ever have bought the product ‘Shoe’. The element function P( ) here returns a list of possible customers; those that are implied by the selection ‘Shoe’ in the field Product.

Which is basically what you are looking for (but with viewers and movies).

Hope it helps.

Best regards.

Re: Movie recommendation engine

Fri, 07 Mar 2014 14:59:01 GMT

Thanks for your reply Luis!

I have read the set analysis text in the Qlikview help section and came up with the following code for my expression in the movie table (with [SERIE TITLE}] as dimension:

sum({$<[MEMBER ID] = P({1<[SERIE TITLE]={‘Castle’}>} [MEMBER ID])>}PRICE)

It doesn't work 😞

Do you see what I am doing wrong?