I have a couple doors in my home that swing open on their own. What causes this and can you suggest a way to fix it.

Most of the doors we install inside our homes today are very light duty. We call them hollow core doors. The frames on these doors are also light and it is easy to twist them when installing them. By simply over tightening a screw in the frame you can pull the entire door out of level. When this happens you can have several results. Your door may be sticky or may swing open or closed on its own. Many times the doors will warp and require extra force to make them latch. In most cases the frames are nicely trimmed and it is not worth tearing out the frame to stop the annoying issues. You can also try to loosen the hinges and place shims in various places under the hinge to try to straighten things up. If you can’t put up with the way the door works it may be necessary to reinstall the door and frame from scratch. Several swinging doors can also indicate a structural problem but this is not common. Always check the hinges as well, if they are loose you will want to add longer/bigger screws to pull the hinge tight again.