Many studies into the impact of technology use on psychological wellbeing rely on flawed measures, researchers say.
Surveys are often used to understand how people use their smartphone and to estimate the amount of screen time they have.
A study has found this method is inaccurate, resulting in different data to that recorded objectively by a device itself.
Researchers from the universities of Lancaster and Bath examined 10 surveys for measuring people’s technology use.
They then compared these so-called self-reports with data from Apple Screen Time, which measures how many minutes people use their phone, how often they pick it up and how many notifications they receive.
Dr David Ellis, of Lancaster University, said there was a “gulf” between the data.
“Many studies that try to understand the impact technologies, especially social media and smartphones, have on behaviour don’t accurately measure usage,” he said.
“If people want to make claims about how technology is ruining lives or to change policies, or give advice to parents, the measurements need to be as good as they can be.
“This study suggests that they are not as good as they can be.”
The study, published in the International Journal of Human-Computer Studies, involved 238 people with iPhone 5 models or above.
They completed a survey, estimating how many hours and minutes they spent on their phone each day.
The group then entered this data from their Apple Screen Time app.
Using the Apple Screen Time data, researchers were able to separate the participants into two groups – low and high users.
There were 92 people who fitted into the high use category based on that data.
However, when self-report data was used, only 52 people were rated as high users.
Brittany Davidson, of the University of Bath, said: “There’s a huge discrepancy between what people think they do and what they actually do.
“People might be worried about how much they use their mobile phone but they might not actually use it a lot.”
She said previous studies had made “grand sweeping statements” such as that smartphones caused people to become depressed.
“It is about clear communication going forward,” Miss Davidson said.
“Having more perspective is never going to be a negative thing.”