Researchers in Australia have been asking partygoers how drunk they think they are.
Unsurprisingly, their research has found drunk people are terrible at judging their level of inebriation. The drunker they get the less accurate they become.
Alcohol Healthwatch director Dr Nicki Jackson says the results would probably be the same here in New Zealand.
"Many people will have many drinks under their belt before they feel extreme effects of intoxication."
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Dr Jackson recommends no more than four drinks at an occasion.
She says the findings of the research, published in journal Drug and Alcohol Review, are particularly concerning for young people.
"They are impaired but they don't feel the effects - this is incredibly dangerous both for themselves and for others."
She says replicating the results here would give policy makers more justification for cracking down on the availability of alcohol.
"They've tried very hard to reduce on-license trading hours in bars and nightclubs, particularly in Auckland - but we need some evidence around the types of blood-alcohol concentrations that patrons are leaving these venues with."
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Taking a sober driver along on your night out, always a good idea, is an even better one if you're afraid you'll drink too much. The study also found as the night goes on, sober people "remain relatively accurate" in their estimations of how drunk their friends are.
But the researchers say it also shows how much responsibility hosts have to look after their guests.
"Highly intoxicated patrons were less able to accurately determine their level of intoxication compared to observers," it read.
"Therefore, the responsible service and consumption of alcohol becomes increasingly dependent upon the venues and staff that provide the alcohol."