Query on Recommendations

Hi,

I have recently started exploring recommendations engine. I am able to push the data to recommendations engine and retrieve it back via view mbox. I have a use case where in based on a category id passed along with view mbox, I want to see the recommendations which has the same category associated with it. So while creating recommendations activity, I chose 'Most Read Articles in this category' as criteria.

While trying to see the appropriate recommendations, I have the following mboxCreate function call 'mboxCreate('mbox-name', 'entity.categoryId=work')' and I have assumed that it will retrieve recommendations whose category matches with the category I have written in the view mbox but I was wrong because I was seeing some random recommendations present in the collection. So could anyone pls suggest me something so that my use case runs fine.