What does the question mean and what does the answer mean? Let's first establish that the answer cannot be right, the only right answer is the creative generates 100% of the effect. Don't believe me? Try doing a campaign while taking away the creative (for example leave the TV screen black for about 30 seconds). I can guarantee that you're brand effect will be zero. (Obviously don't cheat by leveraging this creative idea and the buzz it generates in other media, as obviously the effect that generates would still be attributable to the total creative idea.)
So why didn't Ipsos report 100% but 75%? Because the number represents the analysis of a large number of campaigns and the variance of recall the various campaigns achieve that cannot be explained by media alone. In my mind this means that Ipsos is answering another question, actually one that is much more useful and insightful. The answer represents the state of the industry with respect to the quality differences of creative executions it produces.
So by retrofitting a question belonging to the answer, the conclusion can only be that the state of the creative industry is pretty appalling. The difference between good and bad creative is enormous and we still produce creative so bad that any media buy is a total wastage. No creative is just as bad as the 30" black screen (otherwise Ipsos would have reported 100%) but 75% is still pretty close, some creative is just slightly better than the very cheap to produce 'void'.
Once we'll see consistent quality then the percentage will get smaller and the effect from one creative compared to the next will become more comparable. As the 75% is measured against recall as a proxy for effect I would expect the industry should perform better with this percentage moving to something closer to 25%. Wish Ipsos would have reported this annually so we would have known if there were improvements in the state of the creative industry.
Well, because I love these kind of topics, I would also like to look at the question from a different angle. Why would people ask to understand the effect of the creative vs the effect of the media (if not go gauge the status of the creative industry)? The reason is obvious, because some people are responsible for the creative and others are responsible (and accountable) for the media. But I don't believe you can split them. Creative and media are one package delivering one inseparable experience. I've compared trying to split the two with the question: "When you're having a fun day at the beach, what percentage of the fun is caused by the beach and what percentage by the sun?"
For people that care for the money advertisers spend, this is a very serious matter. I have believed for a long time and I still believe today that the single biggest gain advertisers can make is by combining creative and media into one holistic plan optimizing customer experience: choose the media (or touch point) and creative combination that delivers the right message at the right time. A simple idea but with huge impact on how we view, execute and optimize media planning. An idea that needs the commitment and determination from the brand owner for a proper implementation for its brands.
To end with the good news. Compared to just five years ago, the industry has made huge advances in this area and we've never been more ready to fully implement 'experience planning'. Ipsos, for example, has done great work that I truly respect with regards to creative effects (and testing creative), just google "Ipsos advertising creative" and I guarantee many insightful articles. I've seen media and creative agencies adopting a different way of working and companies like Pointlogic have invested heavily in its ability to cope with experience planning from an analytical and software point of view.