Dr. Edmond Locard, a student of Bertillonage, and the director of the laboratory at Lyon, France, established the first rules of the minimum number of minutiae necessary for identification [1] .

He is also known as the father of Poreoscopy, which is the study of pores that appear in the fingerprint ridge, and their use in the individualization process.  Dr. Locard also realized the value of the shape of the ridge as being permanent, and he should also be known as the father of Edgeoscopy.  

Locard went beyond the variations of the individual friction ridge path which Sir Francis Galton noted as he defined those friction ridge events.  The variations of the individual friction ridge features which he noted, has evolved into "Ridgeology", which is a coined phrase describing the use of those features in the fingerprint identification process.  Dr. Locard should also then be known as the father of "Ridgeology".  

In 1914, Dr. Locard published his conclusions of the fingerprint identification and the criteria that should be used to assure reliability based upon statistical analysis study.  His study showed the following tripartite rule summarized as follows [2] :

  1. If more than 12 concurring points are present and the fingerprint is sharp, the certainty of identity is beyond debate.
  2. If 8 to 12 concurring points are involved, then the case is borderline and the certainty of identity will depend on:
    1. the  sharpness of the fingerprints;
    2. the rarity of its type;
    3. the presence of the center of the figure [core] and the triangle [delta] in the exploitable part of the print;
    4. the presence of pores [poreoscopy];
    5. the perfect and obvious identity regarding the width of the papillary ridges and valleys, the direction of the lines, and the angular value of the bifurcations [ridgeology / edgeoscopy].

Dr. Locard also realized the value and the importance of, and rendered qualified conclusions to the identification process.  

  1. If a limited number of characteristic points are present, the fingerprints cannot provide certainty for an identification, but only a presumption proportional to the number of points available and their clarity.

Many analysts of fingerprints, due to a lack of experience and proper training, believe that Edgeoscopy and Poreoscopy detail can be given the same weight values a Galton detail.  Dr. Locard,  believed that it would take approximately 40 pores in concurrence to establish individuality.  If eight Galton details were needed to establish individuality, then it would require a weighted value for pores (and edge details) of 1/5th for each detail observed.

Misidentifications have occurred, and will continue to occur, due to those analysts who believe that and ending ridge can be replaced by either a single pore or edge detail.

The courts in Daubert demand all of the above to ensure "Dependability" of the Science of Impression evidence.

Probability studies establish repeatability. 

Repeatability establishes Predictability. 

Predictability establishes Reliability. 

Reliability in Forensics establishes Individuality.

Statistical analysis has to be used in studies to predict repeatability and reliability.

Sir Francis Galton determined probability in his study of two persons having the same ridge detail as 1: 6.4 X 10/9th power (6,400,000,000)- The population of the earth in the year 2000.

J.W. Osterburg assigned rarity values in his statistical model and his probability study determined that the odds of two persons having the same ridge detail as 1: 10/20th power (100,000,000,000,000,000,000).  Osterburg determined that Galton's 6.4 X 10/9th equations would be reached in 9 of the most basic Galton characteristics. [3]  J. W. Osterburg, T. Parthasarathy, T. E. S. Raghavan, and S. L. Sclove, “Development of a Mathematical Formula for the Calculation of Fingerprint Probabilities Based on Individual Characteristics,” Journal of the American Statistical Association 72, 772–778 (1977).

Three studies have been conducted by David A. Stoney, Ph.D, and John I. Thornton, D. Crim. (1986-1987) Regarding fingerprint minutia, as well as reliability models [4] .  

The search for science and the requirement for reliability of the forensic sciences are demanded in the practices of the Post Daubert era. 

The need exists for abandonment of the blind faith acceptance of reliability of fingerprints as a positive means of identification, without scientific empirical statistical studies, substantiated by "third level detail" in concurrence with "Galton" detail.


[1] Kingston, C.R.: Kirk, P.L., "La Regle des 12 points dans l'identification par les empreintes:  historique et valeur", Revue internationale de police criminelle, 20(186), 1965 pp 62-69.

[2] Christophe Champod, Institut de Police Scientifique et de Criminiologie BCH/Universite de Lausanne,     " Edmond Locard - Numerical Standards & "Probable" Identifications, Journal of Forensic Identification, 45 (2) 1995, pp136-155

[3] Kingston, C.R.: Kirk, P.L., School of Criminology.  University of California,  Berkeley, United States "Historical development and evaluation of the "12 point rule" in fingerprint identification

[4] Stoney, D.A. and Thornton, J.I., " A Critical Analysis of Quantitative Fingerprint Individuality Models, " Journal of Forensic Sciences, JFSCA, Vol.31, No. 4, Oct. 1986, pp.1187-1216