To help encourage interest in psychometrics, the following
  classic articles and monographs are freely available for
  download.
  - Stout, W. (2002). Psychometrics: From practice to theory
  and back (15 years of nonparametric multidimensional IRT,
  DIF/test equity, and skills diagnostic
  assessment). Psychometrika 67(4) 485-518.
  Stout 2002
  
 
  - Samejima, F. (1972). A general model for
  free-response data (Psychometrika Monograph No. 18).
  Richmond, VA: Psychometric Society. Samejima 1972
  
 
  - Samejima, F. (1969). Estimation of latent ability
  using a response pattern of graded
  scores (Psychometrika Monograph No. 17). Richmond, VA:
  Psychometric Society. Samejima 1969
  
 
  - Herzberg, P. A. (1969). The parameters of
  cross-validation (Psychometrika Monograph No. 16).
  Richmond, VA: Psychometric Society. Herzberg 1969
  
 
  - Mcdonald, R. P. (1967). Nonlinear factor
  analysis (Psychometrika Monograph No. 15). Richmond,
  VA: Psychometric Corporation. Mcdonald 1967
  
 
  - Clemans, W. V. (1966). An analytical and empirical
  examination of some properties of ipsative
  measures (Psychometrika Monograph No. 14). Richmond,
  VA: Psychometric Society. Clemans 1966
  
 
  - Mckeon, J. J. (1966). Canonical analysis: Some
  relations between canonical correlation, factor analysis,
  discriminant function analysis, and scaling
  theory (Psychometrika Monograph No. 13). Richmond, VA:
  Psychometric Society. Mckeon 1966
  
 
  - Burket, G. R. (1964). A study of reduced rank models
  for multiple prediction (Psychometrika Monograph No.
  12). Richmond, VA: Psychometric Corporation. Burket 1964
  
 
  - Paul Kelley, H. H. (1964). Memory abilities: A
  factor analysis (Psychometrika Monograph No. 11).
  Richmond, VA: Psychometric Corporation. Kelley 1964
  
 
  - Tucker, L. R. (1963). Format models for a central
  prediction system (Psychometrika Monograph No. 10).
  Richmond, VA: Psychometric Corporation. Tucker 1963
  
 
  - Stake, R. E. (1961). Learning parameters, aptitudes,
  and achievements (Psychometrika Monograph No. 9).
  Richmond, VA: Psychometric Corporation. Stake 1961
  
 
  - Roff, M. (1952). A factorial study of tests in the
  perceptual area (Psychometrika Monograph No. 8).
  Richmond, VA: Psychometric Corporation. Roff 1952
  
 
  - Lord, F. (1952). A theory of test
  scores (Psychometrika Monograph No. 7). Richmond, VA:
  Psychometric Corporation. Lord 1952
  
 
  - Degan, J. W. (1952). Dimensions of functional
  psychosis (Psychometrika Monograph No. 6). Richmond,
  VA: Psychometric Corporation. Degan 1952