A few weeks ago I approached a household to ascertain if anyone in the household qualified for the survey. A man answered the door and was very polite. He answered my questions which identified someone else in the household who qualified for the survey. He went to ask her for cooperation, but she said no. Because of the layout of the household I could see him approach her at a table in dining room. A few days later I tried again and when I approached the front door I saw it was open with only a screen door between me and my respondent who was sitting at the same table. I knocked politely on the screen door. She got up, marched firmly to the front door and slammed it into my face.