Terminology? Update Glossary?

[DaveJ]

I have searched and searched the Glossary and Forecasters Toolbox under "Education" and find no reference to the following items:

HctX
XPX

What do they mean and where can I find a detailed explanation of how they are computed and applied? I'm not certain this is the correct place for this question, but I thought I'd give it a try. It does seem to me that both the Glossary and Forecasters Toolbox (from 2007!) badly need updating to 2014. Things like SwK% and the like are also not found in either.

[RAY@HQ]

They have been updated since 2007, but you're right that another update is overdue. On my to-do list. Here are the definitions you seek, from the 2014 Forecaster:

HCt= hard hit ball rate x contact rate
HctX= Player Hct divided by league average Hct, normalized to 100
The combination of making contact and hitting the ball hard
might be the most important skills for a batter. HctX correlates
very strongly with BA, and at higher BA levels often does so with
high accuracy. Its success with HR was somewhat limited, probably
due to GB/FB differences. BENCHMARKS: The average
major-leaguer in a given year has a HctX of 100. Elite batters
have an HctX of 135 or above; weakest batters have HctX of 55
or below.

Expected LW power index (xPX) (Bill Macey)
2.6 + 269*HHLD% + 724*HHFB%
Previous research has shown that hard-hit balls are more likely
to result in hits and hard-hit fly balls are more likely to end up
as HRs. As such, we can use hard-hit ball data to calculate an
expected skills-based power index. This metric starts with hardhit
ball data, which measures a player’s fundamental skill of
making solid contact, and then places it on the same scale as PX
(xPX). In the above formula, HHLD% is calculated as the number
of hard hit-line drives divided by the total number of balls put in
play. HHFB% is similarly calculated for fly balls.