Note: This advice is given by the CAP Executive about non-broadcast advertising. It does not constitute legal advice. It does not bind CAP, CAP advisory panels or the Advertising Standards Authority.


In March 2001, the ASA upheld complaints against three brochures that featured computer monitor sizes that were the Cathode Ray Tube (CRT) size and not the visible screen size (Tiny Computers Ltd, Time Computer Systems Ltd and Evesham Micros Ltd, all published 28 March 2001). All three brochures stated in small print that standard industry practice was to measure monitors using CRT size. The ASA accepted that that industry practice existed but nevertheless considered readers would expect the quoted size to be the visible screen size of the monitors. The CAP Executive recommended computer and television retailers, manufacturers and publishers should quote the visible screen size, for example “19’’ Viewable size”. It advised that, if they quote the CRT size, advertisers should explain in the body copy next to the measurement that the quoted size is the CRT size and not the visible screen size, for example “19’’ CRT monitor (18’’ viewable)” or “19’’ CRT monitor (not viewable size)”. Claims such as “19’’ CRT monitor” or “19’’ Cathode Ray Tube monitor” on their own are unlikely to be acceptable because some consumers might not know what the CRT (or Cathode Ray Tube) is or, if they do, might not be aware that it is larger than the viewable screen size. Explaining industry practice in small print or linked footnotes is unlikely to constitute acceptably prominent qualification. That advice applies equally to other measurements that are not the viewable size but might be interpreted as such.

In September 2004, the ASA upheld complaints that the description of television screen sizes in some national press advertisements was misleading because they quoted CRT sizes in inches and visible screen sizes in centimetres. Because the quoted visible screen size was substantially smaller than, and not the metric equivalent of, the imperial measurement of the CRT, the ASA ruled that both tube and screen sizes should be quoted in the same measurement to avoid confusing consumers. The CAP Executive has advised the industry to ensure consistency when quoting measurements.

The Copy Advice team recommends that, when quoting the CRT size, marketers should state the visible screen size in the same measurement and round the figure up or down to the closest equivalent in either centimetres or imperial units (for example “24 inch tube, 22 inch visible screen size” or “61 cm tube, 56 cm visible screen size”). Alternatively marketers may state just the visible screen size in either imperial or metric measurements (DSG Retail Ltd, 22 September 2004).


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