New launches fit neatly into three categories these days: products that are truly ground-breaking, those that are flavour or brand extensions and those whose recipes have been changed - either to take 'nasties' out or to put 'goodies' in.

But divining which of these types of launches will be the most successful is less straightforward, as the progress of the 26 products we flagged up as the star launches in last year's Top Products Survey attest. We have graded products on a scale from one to five, with five being the best, based on their sales performance and impact in the market since launch.

Brand extensions and reformulations have proved popular. The most notable of these is Coke Zero, Coca-Cola Enterprises' answer to rival Pepsi Max, which we have voted this year's ultimate Star Product. Sales of Zero nearly hit the £50m mark in the first nine months after launch and last month it picked up The Grocer Gold Award for best new launch of 2006.

The addition of Omega-3 has paid dividends for two products - Kingsmill Head Start and Flora Omega-3 Plus - both of which have recorded impressive sales as a result of their healthier positioning.

Other successful launches have been based on true blue-sky thinking. Kleenex Anti-Viral, a tissue which claims to help stave off the cold and flu virus, has been a hit with consumers, as has Cadbury's Dairy Milk Melts, which combines the premium positioning of a block chocolate with an impulse format. Arla's Lactofree Milk has also made waves in the milk category.

It's not just the bigger players that are driving innovation either. Leaf UK's Red Band healthier confectionery brand, for example, is expected to generate sales of up to £2m by next year and Town & Country Petfoods' Just Desserts range of puds for dogs has also been a great success.

But, of course, it's not always that simple and some products haven't quite lived up to our expectations. Take Carling C2, for example. The 2% abv lager fills the middle ground between no-alcohol beers and standard 4-5% abv beverages but has a taste more in tune with the latter. Despite such credentials, retail sales since launch indicate it has not performed as well in the off-trade as in the on-trade.

Lactalis McLelland's Seriously Spreadable Cheddar is another example. It broke new ground when it was launched last year with sales of only £685,000 in its first 14 months, but it has struggled to recruit Cheddar consumers to the concept.

Even Birds Eye, which has many great launches under its belt, failed to hit the spot with its gastropub-style premium frozen ready meals.

What does all this show? Apart from the fact The Grocer's crystal ball can occasionally get a bit foggy, it once again demonstrates that NPD is very challenging and success is not guaranteed. Over the page we reveal how all 26 products have got on, with figures provided by Nielsen [MAT 24/02/07] or the companies themselves.