There has been lots of media attention on home invasions due to their frequency and the brutality that accompanies them.
A home invasion is much like a bank robbery when the robbers use force to get what they want. Robbery as defined in Wikipedia is the crime of seizing property through violence or intimidation. At common law, robbery is defined as taking the property of another, with the intent to permanently deprive the person of that property, by means of force or fear. Robbery differs from simple theft, a break-in or burglary on its use of violence and intimidation.
Burglary on the other hand generally involves criminals who prefer the home is without occupants. They may impulsively enter a neighborhood and seek out homes that are dark, no car in the driveway, mail piled up and the doors and windows are left unsecured.
Often they will case a certain home and determine the specifics of when the resident is gone. Often they will make an effort to get a phone number of the home by getting the family name from a placard on the side of the house or from information in the mailbox.
In both situations proper security can reduce risk. In my home the home security system is always on. This means whether home or not, any unlawful intrusion is met with a piecing alarm and an automatic call to the police.