DIP: Basic Hand Valuation

I’ve been distracted tangentially recently.

It started because I was thinking about the 1NT response structure:  in particular the invitational sequences.  This got me thinking again about hand valuation.  If it’s applicable in its basic form anywhere, it’s for auctions like 1NT 2NT and 1NT 3NT (or their DIP equivalents).  This led me (back) to the work of Thomas Andrews.  SD assured me his work was significant, and indeed it is.  You can find it, or get to it, from here

http://bridge.thomasoandrews.com/mozilla.html

It is his hand evaluation work that is of most interest.  As you know, DIP currently uses ppc (Practical Point Count) valuation, where A=4.5, K=3, Q=1.75 and J=0.75.  It would also be reasonable to name this valuation method “Fourths” (you will see why later, apart from the obvious point that it uses a quarter point granularity of sorts).

Though Andrews cautions with the risks of using his current conclusions (and some of his work is ongoing), I am sufficiently impressed to move DIP across to it now.  Specifically, DIP will adopt his “Fifths” evaluator, where

• A=4.0
• K=2.8
• Q=1.8
• J=1.0
• T=0.4

In DIP, we’ll refer to it as fpc (Fifths Point Count).  Like ppc, it shares a 40 point deck with the classic hcp count, which should make conversions and explanations relatively easy when needed.  Also, I have always found it annoyingly difficult to write 1/4, 1/2 or 3/4 in DIP, so am looking forward to being able to simply write “0.8″ or similar where needed.

In time, it may well be that I need to change some of the opening and response ranges to cater for the use of fpc.  We’ll keep them roughly as they currently are, for the present, and cross that bridge when we come to it (that is, after more experience with the method).

I think it is fair to compliment Woolsey as to how close his intuitive thoughts were to Andrews calculated ones, except for the apparent under-weighting of the J.  Scaling “Fifths” to where A=4.5, we see how close Woolsey was (ppc first, then fpc scaled in brackets) …

• A = 4.5 (4.5)
• K = 3 (3.15)
• Q = 1.75 (2.025)
• J = 0.75 (1.125)
• T = n/a (0.45)

Interestingly, Andrews also refers to Martelli’s valuation method (named BUM-RAP) which is geared to suit contracts.  It differs from ppc only in that Q=1.5 and T=0.25.  Nevetheless, I expect with many suit-contract auctions, users of DIP will be going down a different route than simplistic hand-evaluation, so this direction of thinking is not of great short term relevance.

I think I’ll use the change in valuation from ppc to fpc to change this blog’s structure slightly.  I’ll pin the current system, only as far as discussed in the blog, to the front page (and maybe begin a change log).  I’ll then let the current front page go to its “natural” place at the bottom.

Until then!

Regards, DipBridge