I think we all need to take a step back and realize this effort for what it is.
Avanti's limitations and methodology are reasonably spelled out in his preceeding explinations. Too many people jump to the last chapter and don't like the ending. READ and you'll understand. I understand why he does not post raw data; I don't like it, but I understand it. If I want the data, I'll have to fetch it for myself. I see no reason why he would falsify his collected info; to what gain? Further, he's only using manufacturer's data, and his point to FTC involvement regarding credibility is as well founded as any other argument I could put forth for contention, so why fuss over it?
This is not unlike posting VOA's versus UOA's. It's a good jumping off point. It's not a clear analysis of a filter's performance, but then it doesn't claim to be; it is a synopsis of the POTENTIAL for perforamance of each filter, not the RESULT. In out daily lives, we all buy products with some amount of faith that the potential for good results are judged by the inputs we see, and then we hope for the best results. This "study" shows us where to BEGIN; this "study" shows us reasonable criteria to begin making rational decisions. It's not the "end all, be all" final last word.
This study isn't even a statistical one, so I can't nit-pick it from a quality engineer point of view. It's just a good overview based upon what he perceives as characteristics worth consideration.
And yes, I read Consumer Reports; they don't do statistical analysis of their tests either. But they do collect products, use a reasonable method based upon their perception of important characteristics for selective ranking, and make predictions based upon preliminary results. They give raw data for historical reliability, and that's good enough for me when I choose to buy a microwave, or TV, or whatever.
This study shows me what I suspected. I buy Wix/Napa Gold filters from Fleetfilter. They are a darn good filter for a darn good price. Are they the "best"? You'd have to define what "best" means to each person, so I'd say "no, they're not the best for every application". But, they are an undeniable good value with above-average performance.
If anyone wants a true "study" done with statistical analysis, I'll offer this: you provide all the time and money, for all the sample units, and the Particle Count analysis, under true quality-control clinical conditions, and I'll crunch the data. I have access to the computer programs, and the training to utilize the systems. I'll work with you to set up the methodology. But know this, for a true statistical analysis, we'll need a minimum of 30 filters for each design, run on identical vehciles in very similar circumstances, and then we'll need some well-qualified lab to do the PC, run on the same equipment by the same operator, ...
Start to get the picture? The enormity of the financial and time committments begins to become apparent. This is why filter companies use ISO standards for PC and beta results. Large companies have the time and money and resources to attain this type of data. So, Avanti used their data to rank the filters considered by his own critieria.
In light of the lack of MY money or time, I'll just use his synopsis as a good jumping-off point.
