Maltby Playability Factor - which irons are easiest to hit

[cnosil]

I've spent a lot of time comparing the MPFs, my non-scientific testing, and MGS/member reviews and I will say the MPF ratings are not the bible. However, the measurements are good if you know you want an iron with a low COG or high MOI, etc. I got a set of Callaway X-20s new in 2008 and will say that they are certainly very forgiving and "playable" and Maltby's MPF reflects that with a score over 1000. However, are they the best iron for everyone? No. I replaced that set with a used set of 2007 Callaway X-Forged irons and will say I became almost immediately more accurate with my irons, but I gave up some forgiveness. I feel like the full "playability" of irons and woods has not yet been fully or truly quantified by anyone yet. It's partially because golf is very feel based as everyone is different but it's also because there are difficult to measure dynamics in the swing that are difficult to identify and capture. Theoretically, Maltby's methods should be rock solid as they are based on math and the principles of physics but math doesn't capture the full story behind golf clubs. If it did, every club would be built using Maltby's principles that drive the MPF. 
I think a few of the big reasons, the MPF isn't the gospel is because every time you add MOI, blade length, and reduce the COG well below 0.84", you give up feel. A Callaway Big Bertha iron and Titleist MB blade will perform the same on a simulator all things being equal. However, when you put that club in human hands suddenly feel comes into play. You put a Big Bertha iron in the hands of a golfer and they will hit consistent shots. However, if you put that Titleist MB blade in their hands, and they will probably hit shots with more variability, but that variability will include shots more accurate than any from the Big Bertha. I don't have anything to back me up but I think it is because the more compact club heads provide much better feel for exactly where it is in the swing. I think when you make a club head wider and longer, you lose your ability to sense exactly where the club head is in the swing.
I think if you were to add a measurement of the clubhead's volume and insert that into the MPF, you could potentially gain the elusive thing that is missing from the MPF, which is feel.

Unfortunately, I don’t think you can quantify looks or feel. What feels good to one player may feel terrible to another. People talk about feeling the club through the swing. No matter what I have tried, I cannot feel the club through the swing. I feel impact and that is the only way I can assess feel.
As for how a club performs that also unique for each golfer. Club design properties influence how the club rotates and how it moves throughout the players swing.

I swing a lot of differently golf clubs during the year and I really can’t tell them apart other than by how they perform which is influenced by physical design features. People always talk about “feel” and I readily admit that I am biased and believe feel and mechanics are very closely tied together....Mechanics help you train feel. You can’t just start with feel.

[Kansas King]

1 minute ago, cnosil said:

Unfortunately, I don’t think you can quantify looks or feel. What feels good to one player may feel terrible to another. People talk about feeling the club through the swing. No matter what I have tried, I cannot feel the club through the swing. I feel impact and that is the only way I can assess feel.
As for how a club performs that also unique for each golfer. Club design properties influence how the club rotates and how it moves throughout the players swing.

I swing a lot of differently golf clubs during the year and I really can’t tell them apart other than by how they perform which is influenced by physical design features. People always talk about “feel” and I readily admit that I am biased and believe feel and mechanics are very closely tied together....Mechanics help you train feel. You can’t just start with feel.

I agree that you can't fully quantify feel. I would say the way I described feel above isn't necessary the literal feel of the club the swing but you're ability to feel confident that you know exactly where the ball is going to go while you're swinging. I think it's more of a subconscious trait or perceived trait of the golf swing. My support for my feelings on how more compact club heads help is the ever growing product offerings that allow you to blend your sets. Most OEMs now offer blendable sets with the most recent being Srixon. I think the crawl towards blended sets going mainstream is that designers understand there is something to be gained from a more compact head. I haven't seen any written research on why this is though.

I did some digging in Maltby's Complete Book of Golf Club Fitting & Performance and found Maltby kind of goes into what I'm trying to describe on page 642, but even he calls it a mystery. He does note that there are feel differences when swing club heads with varying mass and dimensional properties but he doesn't really dive into it. I think this is an area that could be potentially quantified but to a limit. Ultimately everyone has different preferences and perceived feel but the trends in the types of clubs being manufactured today should give some insights that there is some consensus in the golf community on what works. This is a very nebulous area and I think it is what still makes golf a curious adventure for many. I think most of the progress made in iron designs has been mostly trial and error. I believe computers benefited this process enormously in the '90s as there have been many good designs since then and not many irons produced prior to the '90s have retained popularity outside of maybe Pings.

I think that as golf manufacturers better understand how to model the dynamics of the golf swing, we will continue to see improvements regarding the dimensional properties of clubs throughout sets of irons. I don't expect any paradigm changing technology or design changes but I do expect solid improvements. I think the Ping i15s I play now embody much of my thoughts about golf clubs. The set from 4 - G is very progressive with more compact less offset heads on the shorter clubs and progressively larger and more offset longer clubs. 

I think what we are seeing with many club designs today is companies trying to make their clubs with mass and dimensional properties that offer the best blend of forgiveness and perceived feel. That is why when you look at MPF ratings on new clubs, they actually tend to be lower, even on many of the Maltby designs. 

This post got very windy, my bad.