tl;dr: zscore.chboston.org
That's right: the legendary Boston Pediatric Echo Z-Scores are available now on the web, officially sanctioned by Boston Children's Hospital and everything.
This. Is. Huge.
I have been familiar with Steve Colan's Boston z-score data since way back in the day, circa 1994 or so, when I met Girish Shirali. Girish was trained at Texas/Baylor and these data were in wide use there, obviously having spawned even earlier back in Bean Town. Back then, when somebody mentioned "z-scores" I just assumed they meant the Boston data; in my mind, the terms were synonymous. The idea that other echo z-score equations even existed was something of a foreign concept.
I imagined that the Boston Z-Scores propagated about the community as their (and Baylor's) progeny dispersed, in a z-score diaspora of sorts. Before the web, this was probably the only realistic manner in which this type of information could get disseminated. The concepts, while not difficult to grok, were/are best understood by application- and the tool of that application was a compiled DOS-based computer program. Well, without droning on and on about this and the history of "WF", or "PWF", or "ZSCORE.EXE" as it has variously been known, apparently not everyone got exposed to the genius of that program.
Since then, lots has been published in an effort to come to terms with reference values for pediatric echo. This very website (or rather, series of websites) represents my attempt to assimilate what has been published in the name of pediatric echo z-scores— and not all of it shines with the same brilliance of that now decades-old program. But if you weren't lucky enough to know about the Boston program, or know someone who did, you were kinda of stuck.
Fast-forward to today. The standard by which all other pediatric echo z-score equations are judged has now been re-imagined by it's author as a contemporary tool for everyone. Kudos to you Steve Colan, and on behalf of a grateful community, Thanks!
(Hat tip to Brian Soriano of Seattle Children's for pointing me to the Boston z-score web calculator.)