This section is from the book "Practical Real Estate Methods For Broker, Operator & Owner", by Thirty Experts. Also available from Amazon: Practical Real Estate Methods for Broker, Operator, Owner.
William E. Davies
Hoffman Rule and Its Defects - Davies Rule for Valuing Lots Differing in Depth or Width from Standard Lots - How to Compute Corner Values with the Table - Foreclosure Sales No Criterion of Value - Plottage
Lot Ft | Value | Aggregate per cent | ||
25 | x | 100 | $1,000 | |
10 | x | 25 | 160 | 16 |
15 | x | 25 | 235 | 23.50 |
20 | x | 25 | 310 | 31 |
25 | x | 25 | 375 | 37.50 |
30 | x | 25 | 440 | 44 |
35 | x | 25 | 500 | 50 |
40 | x | 25 | 560 | 56 |
45 | x | 25 | 615 | 61.50 |
50 | x | 25 | 670 | 67 |
Lot Ft. | Value | Aggregate per cent | ||
55 | x | 25 | $715 | 71.50 |
60 | x | 25 | 760 | 76 |
65 | x | 25 | 800 | 80 |
70 | x | 25 | 840 | 84 |
75 | x | 25 | 875 | 87.50 |
80 | x | 25 | 910 | 91 |
85 | x | 25 | 935 | 93.50 |
90 | x | 25 | 960 | 96 |
95 | x | 25 | 980 | 98 |
100 | x | 25 | 1,000 | 100 |
Regarding the Hoffman rule, the compiler has in the past used same in many cases, its application having been stipulated by both parties in several proceedings, but a long and very varied experience in making appraisals as a real estate expert has impressed upon him its frequent inconsistency and the necessity of devising some logical method of valuing lots more or less than one hundred feet in depth.
After studying 10,200 sales and ascertaining the average values of lots of different depths, the compiler adopted the following equation of the parabola in which Y = the proportion of value of lot in question to value of full lot, and X = the proportion of depth of lot in question to depth of full lot (100 feet). Formula of Davies rule:
Y = ![]()
This formula has been tested in several hundred appraisals and found invariably to produce a satisfactory result.
It has, moreover, the inestimable advantage that it can be applied to lots of any depth and not alone to strips varying five feet in depth within the limit of 100 feet, as is the case with the Hoffman rule.
Let us suppose that a corner lot is 25x50 and that the standard inside lot 25x100 is worth $1,000. The ratio for the depth of fifty feet as given in the table is .654. Corners in this neighborhood are worth fifty per cent more than inside lots. This does not mean that $327 (50% of $654) is to be added to the $654 given as the ratio for depth. Merely the ratio of 50% is to be added. Fifty per cent of .654 is .327. This gives the value of the corner as $654 + 32.7% = $868 the proper value of a corner 25x50.
For depths with parts of foot or more than 200 feet, or where greater accuracy is desired than three places of decimals, use the formula in which Y == the proportion of value of lot in question to value of standard lot, and X = the proportion of depth of lot in question to depth of standard lot:
Y = ![]()
 
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