The quantitative weight for a ridge unit type is defined, in general, by multiplying the frequency of its shape (in terms of ridge formation type) to the frequency of its position (in terms of intervening ridge count to nearest neighbor).  The added weight accorded to ridge formations bearing rare intervening ridge counts to its nearest neighbor expand the quantitative weight already established by the frequency of a ridge unit's type.

Expansion factors for different numbers of intervening ridges between nearest neighbors or “ridge count” was applied based on frequency of occurrence.  The number of intervening ridges observed between the two most frequently occurring ridge formation types, the ending ridge and bifurcation, in 39 randomly selected flat fingerprint impressions, was counted.  The percentage distribution and respective quantitative weights (i.e. expansion factors) for each were subsequently defined.  For purposes of simplicity, frequency of occurrence for “0” and “1” ridge counts were combined and equated to a baseline expansion factor equal to 1.  Higher ridge counts and their respective expansion factors were then adjusted in proportion to the baseline.  For purposes of conservativeness, all expansion factors were reduced to the lowest half decimal (Table 5). 

The intervening ridge count between bifurcation designated "A" and ending ridge designated "B" is 1.   The intervening ridge count between ending ridge designated "B" and ending ridge designated "C" is 2. [67]

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For purposes of conservativeness, ridge count expansion factors should be used only for ridge counts that are clearly defined.  Ridge counts between ridge formation types at the periphery of the fingerprint impression should default to the lower ridge count present between the two nearest formation types or between the ridge formation type and the edge of the impression, whichever is less.

Example

The ridge count between an ending ridge located in a non-pattern force area and its nearest neighbor, another ending ridge also located in a non-pattern force area, is 6.  Absent additional values for continuous ridge units and pores, the aggregate quantitative-qualitative weight for this amount of ridge detail is defined as follows:

(14.25 ^ 2) x 188.5 = 39,632