SimplyLED said the claim was based on testing by the manufacturer and third-party testing houses and experience of the product in comparison with various GU10 50 W halogen bulbs, which they believed their product out-performed. They supplied photometric test reports of the cool white and warm white versions of the NxtGen GU10 LED bulb in initial and stabilised states (when the bulb was switched on and some time afterwards) carried out by the manufacturer. They also supplied photometric test reports carried out by a testing house which compared their NxtGen GU10 LED bulb with GE (General Electric) branded 50 W GU10 halogen, Sunbeam GU10 halogen Spotlight 50w, Hyundai 50 W GU10 halogen 550 lumen and Homebase GU10 50 W halogen bulbs.

SimplyLED said the testing-house report, which compared their product with the GE bulb, showed the LED bulb reached a higher lumen level initially and then stabilised to a lower level after a period of time, whereas the halogen bulb had a lower lumen level initially, which increased after a period of time. On the basis that the report showed that the LED bulb achieved a higher initial lumen reading than the halogen and that, after a period of time, the report showed the halogen achieved only a slightly higher reading than the LED, they believed the claim was justified. They said the assessment was based on the warm white version of the LED bulb, whereas the cool white version offered a higher lumen output. They said the testing-house results showed there were wide variances in the lumen output that GU10 50 W halogen lamps achieved; that, in terms of lumen output, their product compared closely with the GE bulb but that their product out-performed most other branded and non-branded GU10 50 W bulbs. They believed most consumers tended to buy the cheaper and more readily available bulbs. They said their claim was further backed by positive feedback from customers but that a claim that referred to "a 50w Halogen" did not necessarily mean that the claim related to every 50 W halogen on the market.

SimplyLED said brightness was subjective and defined by Wikipedia as "... an attribute of visual perception in which a source appears to be radiating or reflecting light. In other words, brightness is the perception elicited by the luminance of a visual target. This is a subjective attribute/property of an object being observed". They said a comparison between lumens and watts was always going to be flawed because a lumen was a measurement of output of light whereas wattage related to the consumption of power. They said there was no standard lumen guideline figure for a GU10 50 W halogen lamp or the lumen output an LED lamp needed to achieve to match a 50 W halogen lamp. They said comparisons assumed that the ratio of watts consumed to lumens emitted was consistent in incandescent and halogen lamps across manufacturers, but that their test results showed that was not the case. SimplyLED said lumen output was a fairly reliable way of estimating the brightness of a bulb but concluded that, to truly determine brightness, factors such as beam angle and colour temperature also needed to be taken into account. SimplyLED said that the wider beam angle of their lamp (60 degrees) compared with that of a GU10 Halogen lamp (38 degrees) meant that a typical room lit by their lamp would appear brighter because their lamp gave a wider spread of light and would cast brightness throughout the room rather than just at a single point on the floor.

SimplyLED said the Kelvin scale measured how white a source of light was, with a higher number equating to a whiter and brighter light. They said the Kelvin rating for their lamp was higher than that of the GU10 halogen lamp.

They said they intended publishing information and test results on their website and to lobby the relevant EU department to bring clarity to the issue.