Labels containing technology specifications and jargon are "misleading people buying new electronic devices" claims Which?
In many cases, the statistics of different brands are not comparable, says the consumer watchdog group.
Shops can add to the confusion by not understanding the significance of the labels either, according to the Which? report.
The firm looked at a range of devices including TVs, cameras, and laptops.
"Televisions make a lot of claims and use a lot of big numbers," said Matt Bath, technology editor at Which?
"One set claimed to have 'four trillion colours' - which sounds fantastic. The trouble is, programmes aren't broadcast in that many colours and in any case, we can't see that many; it's meaningless."
He also warned consumers against comparing statistics - such as contrast ratios between different sets - because the manufacturers do not have a common standard, so the numbers they use are not the same.
Televisions marked 100Hz, 200Hz, and 600Hz are also not measurements of the same specification, although they can be presented as if they are, Mr Bath told BBC News.
100Hz and 200Hz relates to the number of times a screen refreshes itself per second. However, 600Hz refers to the so-called sub-field drive - a method used to flash the individual dots on a plasma screen. The number states how often they flash every second.
"It's like comparing two cars when one claims to reach 100 miles per hour and another 1000 revs per minute," said Mr Bath.
Digital camera marketing also came under scrutiny. Some devices claim to have an impressive "digital zoom" rate, but this simply means that they enlarge part of the original image, rather than refocus the lens (optical zoom), according to the report.
"It's certainly marketing hype," said Mr Bath.
"Plastering products with big numbers will make some consumers choose the brand which sounds more impressive. But when it comes to technology, bigger doesn't mean better."