PSA: Lumping people together in the 50+ age group is a terrible idea — from a business perspective and, well, a general one, too.

According to research by Gransnet and Mumsnet, social networking websites for grandparents and parents in the UK, a whopping 78 percent of people age 50 or older feel misrepresented in the advertising space. The why boils down to this — 62 percent believe their lifestyle factors are disregarded by advertisers due to a lack of understanding by young professionals in the business, reports Marketing Week. Yikes.

“If advertisers want to talk to the over-50s, who have more disposable income than any other age group, they need to start by listening to them,” said Gransnet editor Lara Crisp.

So what fields are seriously lacking when it comes to customizing ads to these folk? Technology rings in at number one, specified by 87 percent of test subjects. Next up is fashion at 84 percent, and last but not least, entertainment at 79 percent.

The statistics were revealed at a global marketing festival held in London.

“It is down to brands to tackle [outdated] assumptions and ad agencies to ask harder questions,” said speaker Tom Goodwin, head of innovation at Zenith. “And we need to get out there in the real world and see how normal people behave, so it is less about cliché tactics and more about the interesting things that connect with older people.”

The bottom line, here, is this: Advertisers should throw out stereotypes about unfamiliar generations — especially the older ones — and explore what they would prefer them to account for in marketing strategy.