Videocassette recorders (VCRs) enable people to watch movies at home on videotape  People who own VCRs go to movie theaters more often than do people who do not own VCRs
Contrary to popular belief, ttherefore, owning a VCR actually stimulates people to go to movie theaters more often than they otherwise would
fails to establish that the phenomena interpreted as cause and effect are not both direct effects of some other factor