John I. McCool, Ph.D.

Distinguished Professor of Systems Engineering

Engineering Division


    • Reliability theory
    • Tribology
    • Measurement analysis of rough surfaces
    • Experiment design, data mining and QC
    • Established Penn State Great Valley surface microtopography laboratory in 1991

Professional Activities


    • Fellow of the ASQ, 2005
    • Philadelphia ASQ Section Hoffer Award for Promoting Statistical Thinking, 2000
    • Penn State Great Valley Faculty Senate's Award for Research, 1999
    • Penn State Great Valley Faculty Senate's Award for Service 1995


    • Ph.D. - Temple University, Statistics
    • M.S. - Drexel University, Mechanical Engineering
    • B.S. -  Drexel University, Mechanical Engineering


    • IN SC 525 – Applied Data Mining
    • SYSEN 530 – Systems Optimization
    • SYSEN 531 – Probabilistic Modeling and Simulation
    • SYSEN 597 – Engineering Management Science
    • STAT 500 – Applied Statistics
    • IE 511 – Experimental Design in Engineering
    • IE 532 – Reliability Engineering
    • IE 566 – Quality Control

Research Interests

    • Inference on the Weibull life distribution  
    • Microcontact models 
    • Warranties and control charts


Articles Published in Refereed Journals

McCool, J.I. 2011. Software for Weibull Inference. Quality Engineering, 23:253-264.

Phan, L. D. and McCool, J. I. 2009 Exact confidence intervals for Weibull parameters and percentiles. Proc. IMechE, Part O: J. Risk and Reliability, 223 (4), 387-394. DOI 10.1243/1748006XJRR247

McCool, J. 2009. Design of Sudden Death Tests for Estimation of a Weibull Percentile, Journal of Testing and Evaluation, 37: 311:315.

McCool, J. and Valori, R. 2009. Evaluating the Validity of Rolling Contact Fatigue Test Results, Tribology Transactions, 52:223-230.

Wan, Q, Sheffield, J. McCool, J. and Baran, G. 2008. Light Curable Dental Composites Designed with Colloidal Crystal Reinforcement, Dental Materials 24: 1694-1701.

McCool, J. 2006. The Distribution of the Present Value of a Pro Rata Warranty Policy, International Journal of Industrial Engineering, 13:395-401.

McCool, J. 2006.  Control Charts for Radial Error, Quality Technology and Quantitative Management 3:283-292.

McCool, J. 2006 Testing for Dependency of Failure Times in Life Testing, Technometrics, 48: 41-48.

McCool, J. I., 2004.  Statistical Error in Crack Growth Parameters Deduced from Dynamic Fatigue Tests.  International Journal of Fatigue, 26, pp. 1206-1215.

Debnath, S., Wunder, S., McCool, J. and Baran, G., 2003. Silane Treatment Effects on Glass/Resin Interfacial Shear Strengths, Dental Materials 19:441-448.

Boberick, K., McCool, J, and Baran, G., 2002, Strength and Fatigue of Polyacid-Modified Restorative Materials (Compomers), Journal of Material Science:Materials in Medicine 13:613-620

Baran, G., Boberick, K., and McCool, J., (2001).  "Fatigue of Restorative Materials, Critical Reviews in Oral Biology and Medicine, 4:350-360.

McCool, J. I., K. G. Boberick, and G. Baran. (2001). "Lifetime Predictions for Resin-Based Composites Using Cyclic and Dynamic Fatigue." Journal of Biomedical Material Research (Applied Biomaterials) 58: 247-253.

McCool, J., 2000. Extending the Capability of the Greenwood Williamson Microcontact Model. Journal of Tribology, Transactions of the ASME,122:496-502.

McCool, J., 2000. Exact Ad Hoc Inference from Weibull Samples. International Journal of Industrial Engineering, 7:26-32.

Baran G., McCool, J., Boberick, K. and Zhang, H., 1999. Size Effect in Resin/Glass Composite Flexure Strengths. Journal of Oral Rehabilitation, 26:775-780

McCool, J. and Baran, G. 1999. The Analysis of 2x2 Factorial Fracture Experiments with Brittle Materials. The Journal of Material Science 34:3181-3188

Boberick, K. and McCool J. 1998. Dimensional Stability of Record Bases Fabricated from Light Polymerized Composites Using Two Methods. The Journal of Prosthetic Dentistry 79:399-403.

Baran, G., McCool, J., Paul, D., and Wunder, S. 1998. Weibull Models of Fracture Strength of Dental Resins in Flexure and Shear. Biomedical Materials Research (Applied Biomaterials) 43:226-233.

McCool, J., and Joyner-Motley, T. 1998. Control Charts Applicable when the Fraction of Nonconforming Items is Small. Journal of Quality Technology 30:240-247.

McCool, J., 1998. A Constrained Access Repairman Problem. International Journal of Industrial Engineering 5:140-148.

McCool, J. 1998. Inference on the Weibull Location Parameter., Journal of Quality Technology, 30:119-126.

McCool, J., 1996. The Analysis of a Two Way Factorial Design with Weibull Response. Communications in Statistics-Simulation, 25:263-286.

Harris, T., and McCool, J., 1996. On the Accuracy of Rolling Bearing Fatigue Life Prediction. ASME Transactions, Journal of Tribology, 118:297-310.

McCool, J. 1996. The Analysis of Two Factor Rolling Contact Fatigue Test Results. Tribology Transactions, 39:59-66.

Melloy, B., McCool, J., and Rosenshine, M 1992. Determining the Production Lot for Precision Components. Journal of Statistical Computation and Simulation 41:1-18.

McCool, J. 1992. Nongaussian Effects in Microcontact. Int. J. Mach. Tools Manufact. 32: 115123.

McCool, J. 1991. Inference on P[Y<X] in the Weibull Case. Commun. Statist.Simula., 20: 29148.

McCool, J. 1990. Evaluating the TevaarwerkJohnson Elastic/Plastic Traction Model in the Presence of Lateral Sliding and Spin. STLE Transactions 33:122130.

McCool, J., and John, J. 1988. Flash Temperature on the Asperity Scale and Scuffing. ASME Transactions, Journal of Tribology 110: 659-663.

McCool, J. 1988. Predicting the Upper Percentiles of Flash Temperature at Microcontacts. Surface Topography 1:343-355.

McCool, J. 1988. The Distribution of Microcontact Area, Load, Pressure and Flash Temperature Under the Greenwood Williamson Model. ASME Transactions, Journal of Tribology 110:106-111.

McCool, J. 1987. Relating Profile Instrument Measurements to the Functional Performance of Rough Surfaces. ASME Transactions, Journal of Tribology 19:264-270.

McCool J. 1986. TRIBOS: A Performance Evaluation Tool for Traction Transmitting Partial EHD Contacts. ASLE Transactions 29: 432-440.

McCool, J. 1986. Predicting Microfracture in Ceramics Via a Microcontact Model. ASME Trans, Jnl of Tribology 108:380-386.

McCool, J. 1986. Comparison of Models for the Contact of Rough Surfaces. Wear 107:37-60.

McCool, J. 1986. Using Weibull Regression to Estimate the Load-Life Relationship for Rolling Bearings. ASLE Transactions 29: 91-101.

McCool, J. 1984. Assessing the Effect of Stylus Tip Radius and Flight on Surface Topography Measurements. ASME Transactions, Journal of Tribology 106:202-210.

Morrison, F., McCool, J., Yonushonis, T., and Weinberg, P. 1984. The Load-Life Relationship for M50 Steel Bearings with Silicon Nitride Ceramic Balls. Lubrication Engineering 40:153-159.

McCool, J. 1983. Limits of Applicability of Elastic Contact Models of Rough Surfaces. Wear 86:105-118.

McCool, J. 1982. Finite Difference Spectral Moment Estimation for Profiles: The Effect of Sample Spacing and Quantization Error. Precision Engineering 4:181-184.

McCool, J. 1980. Confidence Limits for Weibull Regression with Censored Data. IEEE Transactions on Reliability R-29:145-150.

McCool, J. 1979. Systematic and Random Errors in Least Squares Estimation for Circular Contours. Precision Engineering 1:215-220.

McCool, J. 1979. Estimation of the Weibull Shape Parameter for Samples of Size 2. IEEE Transactions on Reliability 28:158-160.

Tallian, T. and McCool, J. 1978. A New Explanation of Fatigue Life Dispersion in Rolling Contacts. Wear 47:147-154.

McCool, J. 1978. Characterization of Surface Anisotropy. Wear 49:19-31.

McCool, J. 1978. Competing Risk and Multiple Comparison Analysis for Bearing Fatigue Tests. ASLE Transactions 21: 271-284.

McCool, J. 1976. Estimation of Weibull Parameters with Data Censored by a Competing Weibull Failure Model. IEEE Transactions on Reliability R-25:25-31.

McCool, J. 1975. Multiple Comparisons for Weibull Parameters. IEEE Transactions on Reliability R-24:186-192.

Liu J., McCool, J. and Tallian, T. 1975. Dependence of Bearing Fatigue Life on Film Thickness to Surface Roughness Ratio. ASLE Transactions 17: 144-152.

McCool, J. 1974. Analysis of Sudden Death Tests of Bearing Endurance. ASLE Transactions 17: 8-13.

Tallian, T. and McCool, J. 1971. An Engineering Model of Spalling Failure in Rolling Contact-The Surface Model. Wear 17: 447-461.

Chiu, Y., Tallian, T., and McCool, J. 1971. An Engineering Model of Spalling Fatigue Failure in Rolling Contact-The Subsurface Model. Wear 17: 433-446.

McCool, J. 1970. Inference on Weibull Percentiles and Shape Parameter from Sudden Death Tests Using Maximum Likelihood Estimates. IEEE Transactions on Reliability R-19:177-179.

McCool, J. 1970. Inference on Weibull Percentiles and Shape Parameter from Maximum Likelihood Estimates. IEEE Transactions on Reliability R-19: 2-9.

McCool, J. 1970. Evaluating Weibull Endurance Data by the Method of Maximum Likelihood. ASLE Transactions 13:189-202.

McCool, J. 1970. Load Ratings and Fatigue Life Prediction for Ball and Roller Bearings. Journal Lubrication Technology 92: 16-22.

McCool, J. 1969. Unbiased Maximum Likelihood Estimation of a Weibull Percentile When the Shape Parameter is Known. IEEE Transactions on Reliability R-18:78-79.

McCool, J. 1969. Graphical Determination and Uses of Order Statistics Quantiles. Journal Quality Technology 1: 237-241.

Chiu, Y., Tallian, T., McCool, J., and Martin, J. 1969. A Mathematical Model of Spalling Fatigue Failure in Rolling Contact. ASLE Transactions 12:106-116.

Tallian, T., and McCool, J. 1968. The Observation of Individual Asperity Interactions in Point Contact. ASLE Transactions 11:176-190

McCool, J. 1966. Inference from the Third Failure in a Sample of Size Thirty from a Weibull Distribution. Industrial Quality Control 23:109-114.

Tallian, T., Brady, E., McCool, J., and Sibley, L. 1965. Lubricant Film Thickness and Wear in Rolling Point Contact. ASLE Transactions 8: 411-424.

McCool, J. 1965. The Construction of Good Linear Unbiased Estimates from the Best Linear Estimates for a Smaller Sample Size. Technometrics 7: 543-552.

Articles in Refereed Proceedings

Harris, T., and McCool, J. 1995. On the Accuracy of Rolling Bearing Fatigue Life Prediction. Proceedings of ASME/STLE Annual Tribology Conference preprint No. 95- TRIB-31.

McCool, J. 1990. Elastic Contact of Coated Rough Surfaces. Proceedings of the Leeds-Lyon Symposium on the Mechanics of Coatings 16:157-165.

McCool, J. and Popgoshev D. 1986. Effect of Asperity Interactions on Scuffing. Proceedings of the Leeds-Lyon Symposium 12:135-145.

McCool J. and Gassel, S. 1981. The Contact of Two Surfaces Having Anisotropic Roughness Geometry. Proceedings of the ASLE Energy Sources Technology Conference, ASLE Spec. Publ. SP-7: 29-38.

McCool, J. 1973 Censored Sample Size Selection for Life Tests. Proceedings IEEE Annual Reliability and Maintainability Symposium IEEE Cat. No.73CHO714-64:280-288.

McCool, J. 1968 Estimation and Confidence Limits for a Weibull Sample from Sudden Death Tests. Transactions of the ASQC Annual Technical Conference 22: 747-751.

Tallian, T., McCool, J., and Sibley, L. 1965. Partial Elastohydrodynamic Lubrication in Rolling Contacts Proceedings of Symposium on Elastohydrodynamic Lubrication.Paper 14, Inst. Mech. Engrs.:122-137.

Papers Refereed by Abstract

McCool, J. 1999 Life Test Sample Size Selection Under a Weibull Failure Model. Paper No. 1999-01-2860. Society of Automotive Engineers Technical Paper Series.

McCool, J., Jayaraman, S., Paul, D., Boberick, K., and Baran, G. 1997. Predicting Failure Probabilities of Dental Restorative Resins Using CARES/LIFE., Microfiche proceedings of the Dental Materials Group of International Association of Dental Researchers, 75th Annual Meeting, Orlando FLA, March.

McCool, J. 1993. The Analysis of a Two Way Factorial Design with Weibull Response. Proceedings of the Section on Physical and Engineering Sciences American Statistical Association 153:83-89.

McCool, J. 1987. Recent Results in the Use of Microcontact Models in Tribology. Proceedings 1987 Bearing Conference, DoD/Instrument Bearing Working Group. 2:1-20.

McCool, J. 1985. Surface Roughness Data Analysis. Proceedings of the Third Symposium on Energy Engineering Sciences NTIS CONF-8510176: 223-231.

Tallian, T. and McCool, J. Lubricant Pressure Rippling in Dynamic Hertzian Contacts Induced by Surface Roughness. 1974. Proceedings of 19th Meeting of the Mechanical Failures Prevention Group, National Bureau of Standards Special Publication. 394:62-73.

Book Chapters

McCool., J. 1995. "The Lateral Compliance of Rough Surface Contacts in the Presence of Coulomb Friction.", in Contact Mechanics II, ed. M. Aliabadi, and C. Alessandri, Southhampton U.K: Computational Mechanics Publications. pp. 131-139.

McCool, J. 1991. "Statistical Methods to Analyze Endurance." In Rolling Bearing Analysis. ed. T. Harris. New York:Wiley Interscience. pp. 805-828.

McCool, J. 1991. "Microcontact Phenomena" In Rolling Bearing Analysis. ed. T. Harris. New York:Wiley Interscience. pp. 513-537.

Sundaresan. S., and McCool, J. 1986. "Design and Analysis of Single Factor Experiments with Weibull Response." In Reliability and Process Control, ed. C. Ravindran and S. Sundaresan, Toronto:American Society of Metals, pp. 185-201.

McCool, J 1982. "Analysis of Sets of Two-Parameter Weibull Data Arising in Rolling Contact Endurance Testing." In Rolling Contact Fatigue Testing of Bearing Steels (ASTM STP 771), ed. J. Hoo. Philadelphia:ASTM., pp. 293-319.

McCool, J. 1982. "Censored Data." In Encyclopedia of Statistical Sciences, Vol. 1, ed. N. Johnson and S. Kotz. New York: John Wiley and Sons. pp 389-396.

McCool, J. 1977. "Analysis of Variance for Weibull Populations." In The Theory and Applications of Reliability, ed. C. Tsokos and I. Shimi. London: Academic Press pp.335- 379.

Technical Reports

Russell, D., McCool, J., and Jablokow, K., "The Management of a System of Complex Systems", Final Report Submitted to Lockheed Martin Co., (July 1998) .

McCool, J. I., "Results of Experimental Study of the Effects of Process Variables on Surface Finish and Form", Final Report submitted to Weldon Machine Tool Inc., (July 1992).

Chandra, M. J., McCool, J.I., and Soyster, A., "Improving Product Quality In ASO Contracting", submitted to the Department of the Navy, Naval Aviation Supply Office, Philadelphia PA, (May, 1991)

McCool, J.I., "Life of Concentrated Contacts in the Mixed EHD and Boundary Film Regimes", Final Report on Navy Contract No. N00140-83-C-7149, Naval Air Propulsion Center Report No. NAPC-PE-204C, AD A 216 673. (August, 1989).

McCool, J.I., "Traction Model Development -Final Technical Report", Air Force Materials Laboratory, Wright-Patterson Air Force Base, Technical Report No. AFWAL-TR-87-4079, NTIS ID No. AD A 188 450 (September 1987).

McCool, J.I., "Traction Model Development-Interim Technical Report", Air Force Materials Laboratory, Wright-Patterson Air Force Base, Technical Report No. AFWAL-TR-85-4142, (May 1986).

J. I. McCool, J. I., "Lubrication of Engineering Surfaces", Final Report, Submitted to Department of Energy, DOE Report No. DOE/ER/10693-T1, NTIS ID No. DE84005685, (Dec. 1983).

Morrison, F. R., McCool, J.I., and Ninos, N.J.,"M50 Steel Bearing Material Factors for Rolling Element Life Calculations - Phase II", U.S. Army Aviation Research and Development Command Technical Report TR79-48, (August 1979)

Morrison, F. R., McCool, J.I., and Ninos, N.J.,"M50 Steel Bearing Material Factors for Rolling Element Life Calculations", U.S. Army Aviation Research and Development Command Technical Report TR79-35, (April 1979).

McCool, J.I., ""Inferential Techniques for Weibull Populations II", Aero Space Research Laboratory Wright-Patterson AFB, Final Technical Report ARL TR-0233, AD-AO23937, (June 1975).

McCool, J.I., Chiu,Y., Crecelius,W., Liu, J., and Rosenlieb, W. "Final Technical Report on Influence of Elastohydrodynamic Lubrication on the Life and Operation of Turbine Engine Ball Bearings - Bearing Design Manual ", Air Force Aero Propulsion Laboratory . Wright-Patterson AFB, Technical Report AFAPL-TR25, AD A 020 500. (May 1975.)

McCool, J.I., "Inferential Techniques for Weibull Populations", Aerospace Research Laboratory, Wright Patterson AFB. Interim Technical Report ARL TR74-0180, AD A 009 645, (December 1974).

Chiu, Y. P., Hahn, D., and McCool, J. I., Final Summary Report on "Exploratory Analysis of Elastohydrodynamic Properties of Lubricants", SKF Report No. AL72P010, U.S. Navy Contract NOOO19-71-C-0425, AD 902 283, (1972).

McCool, J.I., et al, Summary Report on " Elemental Contact Occurrences in Rolling and Sliding", SKF Report No. All66L039, U.S. Navy Contract No. AL66L039, U.S. Navy Contract No. NOnr-4895(00), AD 800 058, (1966).

McCool, J.I. et al, Final Summary Report "Influence of Lubrication on Endurance of Rolling Contacts", SKF Report No. AL64l067, AD 609 437 (1964).

McCool, J.I. and Gustafsson O.G., Special Report on "Relative Axis Motion Induced by Variable Elastic Compliance in Ball Bearings" SKF Report L60L023, U.S. Navy Contract No. NObs-78552, AD 670 620, (1960).