Cards: single column or multiple columns

Question

I'm working a card-based UI concept which allows grouping. As an example I look at a person and see his tasks and documents (and there could be many more categories):

So far so good. Now if I only have one column, it would make sense to use all available space. I could show within one card-column 3 rows (this could mix up, like: column (2rows), 2nd column (1 row), 3rd column (1row).

I'm nut sure if this is easily understandable. Google Plus uses 3 rows of cards, but they main purpose is exploring and not searching.

What is the trade-off to have more cards visibile at once vs. more effort of scanning by using multiple columns?

Answer 1

It makes sense to have multiple columns if:

1. Your interface is wide and you need to make better use of space. This will be a tradeoff with scan-ability / readability, so you shouldn't do it simply because you have the space.
2. The logical columns have (or can have) different semantic meanings. In your first example, having two columns makes a lot of sense because they represent different things. Your second example may work, but just by looking at it I can't tell whether it overflows left-right-left or top-down-top, so I'm sure other users will face the same uncertainty. If you're confident (user testing) that this won't be an issue for you users, then go for it. But the only way you're really going to know is by doing user testing.