The study, by data firm GB Group, involved the monitoring of direct mail received by the O'Callaghan family, who consist of husband and wife Michael and Carol, and their two daughters, Katie and Gaynor, who live near Chester.
The study found that around 45% of mail was not addressed to specific members of the family and when it was, mail was often poorly targeted.
In one of the more extreme examples, the youngest daughter Gaynor was sent a mail shot by a property investment firm, despite being the least likely to be interested in such an offer.
Ian Davidson, GB group managing director, said: "Our family confirmed that they virtually never opened direct mail that was not specifically addressed to a member of the household, and even if the mail was addressed to them personally they would not open it unless it appealed to them as consumers."
Despite poor targeting, overall one of the best sectors was financial services, which on the whole did manage to offer the highest credit deals to the parents rather than their children.
According to Carol O'Callaghan: "It was interesting to actually track the amount of direct mail we received. Very little of it was relevant to us. Many of the catalogues which came through the door were for products we have very little or no history of buying."
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