missing the litterbox

My cat is litterbox trained, however, he seems to have trouble 'aiming' when he poops. When he urinates, he does fine, but when he does other business, it often ends up on the side of the box or in the floor. And even if it does end up in the litter, he never covers it up. Is there a way to teach him to actually aim for the box? I've heard that this is something that they learn from their mother cat, but since I got him from a shelter, I have no idea what the situation was before. I guess I should be grateful that he at least confines it to one area, but its a little annoying and smelly sometimes... Thanks for you help!

The best solution for this common problem is to use a larger litter box. Try getting a rubbermaid under-bed storage container. Discard the lid and fill with litter. I think you will find that this problem stops immediately once the large box is in place!

Or a covered litterbox!