A CROSS-VALIDATION OF THE FACTOR STRUCTURES OF CHRONOTYPOLOGICAL QUESTIONNAIRES
Dmitriy A. Putilov

Presented as a poster:
11th Eur. Conf. on Personality, Friedrich-Schiller-University Jena, 21.7.-25.7.2002

OBJECTIVES
The aim of the study was to evaluate psychometrically a questionnaire battery for assessment of the individual traits of sleep-wake patterns. 

SAMPLES AND METHODS
Two English language questionnaires with 4 scales/subscales (Folkard et al., 1979; Horne, Ostberg, 1976) and two Russian language questionnaires with 6 scales/subscales (Putilov, 1990, 1997, 2000) were included in the list of 92 questions/statements. After translation and minor rewording, the English version of the battery was given to the students of the University of Alaska, and the Russian version was given to the students of the Novosibirsk State University. 

RESULTS 
It was found that both versions are almost identical on 
1) Cronbach alpha for any scale/subscale (Table 3), 
2) magnitude of the difference between age and gender groups on the mean scores (Table 2), 
3) correlation patterns between the scales/subscales’scores (Table 1), 
4) factor structure of the whole battery (Table 4), and 
5) factor structure of the 40-item Sleep-Wake Pattern Assessment Questionnaire (SWPAQ; Putilov, 1990) (Table 4 and Table 5). 
Besides, the latter result was also in agreement with the earlier obtained results (Putilov, 1993) for a general population sample of 2000 males and 2126 females aged 9 to 79 yrs (Table 5). 
CONCLUSION
The subjectively assessed individual differences in the habitual features of the sleep-wake cycle seem to reflect the underlying differences in the parameters of chronophysiological regulatory mechanisms. 

REFERENCES
Folkard S, Monk TH, Lobban MC (1979): Towards a predictive test of adjustment to shift work. Ergonomics 22, 79-91.
Horne JA, Östberg O (1976): A self-assessment questionnaire to determine morningness-eveningness in human circadian rhythms. Int J Chronobiology, 4, 97-110.
Putilov AA. (1990): A questionnaire for self-assessment of individual traits of sleep-wake cycle. Bull. Siberian Branch of the USSR Academy of Medical Sciences, 1: 22-25.
Putilov AA (1993) A questionnaire for self-assessment of individual profile and adaptability of sleep-wake cycle. In: Gutenbrunner C, Hildebrandt G, Moog R (Eds.): Chronobiology and Chronomedicine 1991: Basic Research and Applications. Peter Lang, Frankfurt am Main et al., pp. 492-498.
Putilov AA (1997): "Owls", "Larks" and Others: About Clocks Inside Us and Their Influence on Our Health and Character. Novosibirsk: Novosibirsk University Press; Moscow: Publishing House "Soverschenstvo".
Putilov, A.A (2000): Association of the circadian phase with two morningness-eveningness scales of an enlarged version of the sleep-wake pattern assessment questionnaire. In: Hornberger S., Knauth P., Costa G., Folkard S. (eds): Shiftwork in the 21st Century: Challenges for Research and Practice. Peter Lang: Frankfurt et al., pp. 317-322.

Appendix

List of scales and subscales:
40-item Sleep-Wake Pattern Assessment Questionnaire (10 tetrads of 4-item statements each):
      M-scale - level of morning wakefulness (positive score indicates morning lateness)
      E-scale - level of evening wakefulness (positive score indicates evening lateness) 
      S-scale - quality of night sleep (positive score indicates deep sleep) 
      w-sub-scale - capacity to stay awake at anytime (positive score indicates better wakeful ability)
      f-sub-scale - capacity to fall asleep at anytime (positive score indicates better sleep ability)
20-item Folkard circadian type questionnaire:
      v-sub-scale - vigorousness/languidiness or inability/ability to overcome drowsiness (higher score indicates inability)
      r-sub-scale -  rigidity/flexibility  of  sleeping habits (higher score indicates rigidity)
      m-sub-scale - morningness-eveningness (higher score indicates morningness)
Morningness-eveningness questionnaires:
      13-item Russian (ME) scale (higher score indicates morningness)
      19-item Horne-Ostberg (Me) questionnaire (positive score indicates eveningness)     

Table 1. Correlations matrix of four questionnaires scores
         (above the diagonal - Russian version, n = 180)
         (below the diagonal - English version, n = 160)
______________________________________________________________________
        !      FOLKARD Q   !  HOQ!Scale! SLEEP-WAKE PATTERN A. Q
        !   r     v     m  !  ME !  Me !  M     E     S     w     f
----------------------------------------------------------------------
     r  ! 1.00   .11   .27'" .16'  .03  -.14  -.16' -.35'"-.27'"-.22"
        !      \\
     v  ! -.11  1.00   .06  -.02   .00   .07  -.31'" .04  -.33'" .05
        !            \\
     m  !  .16   .06  1.00   .49'"-.27'"-.46'"-.32'"-.03  -.06  -.08
-------------------------- \\   --------------------------------------
     ME !  .28'"-.12   .54'"1.00  -.63'"-.59'"-.43'"-.10   .03  -.07
-------------------------------- \\   --------------------------------
     Me ! -.25"  .19' -.44'"-.80'"1.00   .46'" .43'"-.12  -.16'  .15'
-------------------------------------- \\   --------------------------
     M  ! -.36'" .40'"-.45'"-.63'" .58'"1.00   .37'" .06  -.02   .15'
        !                                     \\
     E  ! -.29'"-.12  -.38'"-.61'" .52'" .37'"1.00   .15'  .23'" .11
        !                                          \\
     S  ! -.36'"-.02  -.04   .06  -.11  -.02   .12  1.00   .16'  .17'
        !                                                \\
     w  ! -.13  -.21" -.10  -.05  -.05  -.12   .18'  .13  1.00   .18'
        !                                                      \\
     f  ! -.45'" .08   .00  -.04   .09   .09   .07   .25"  .12  1.00
______________________________________________________________________
Note. Level of significance of the correlation coefficient:' p < 0.05, " p < 0.01, '" p < 0.001

Table 2. T-test comparison  of mean questionnaire scores of Russian and English versions in  female (n=87,103) and male students (n=93, 54)
___________________________________________________________________
scale   ! sex ! 2-tailed t-test!                 !                !
        !     !    t       p   ! Mean   Std.Dev. ! Mean  Std.Dev. !
--------!-----!---------------------------------------------------!
     r  !fem. !  0.09   .929     40.87   12.87     40.67   16.29  !
        !male ! -1.61   .108     37.20   12.58     40.95   15.09  !
     v  !fem. !  3.01   .003     63.96   15.67     57.49   13.93  !
        !male !  2.58   .011     55.40   17.07     47.79   17.34  !
     m  !fem. ! -1.38   .169     55.68   14.67     58.61   14.48  !
--------!male ! -3.01   .003     51.10   14.75     58.56   13.93  !
     ME !fem. !   .67   .504     49.97    7.24     49.15    9.29  !
--------!male !  -.80   .421     47.77    8.22     48.92    8.54  !
     Me !fem. !   .48   .626     -1.75    6.19     -2.26    7.75  !
--------!male !  2.48   .014      1.35    7.31     -1.98    8.67  !
     M  !fem. !  -.40   .688      1.17    5.66      1.51    5.98  !
        !male !  1.16   .247      1.97    5.62       .88    5.20  !
     E  !fem. ! -2.37   .019      -.59    3.47       .77    4.34  !
        !male !  -.62   .533      2.06    4.40      2.50    3.42  !
     S  !fem. !  4.92   .000      5.37    5.32      1.24    6.13  !
        !male !  3.99   .000      5.67    4.45      2.25    5.82  !
     w  !fem. !  -.77   .442      -.66    2.58      -.36    2.71  !
        !male ! -1.67   .095      -.36    2.43       .37    2.77  !
     f  !fem. !  -.69   .487      -.29    2.43      -.03    2.67  !
--------!male !   .62   .536       .53    2.18       .29    2.40  !
 a g e  !fem. ! -6.89   .000     19.39    1.60     25.79    8.53  !
        !male ! -3.14   .002     20.98    2.56     23.31    6.30  !

----------------------------------------------------------------------------------------------

Table 3. Cronbach alphas for 10
scales and subscales of four
chronobiological questionnaires
   
   ------------------------
   scale,   !   Version   !
   subscale ! Russ.! Engl.!
   ------------------------
    r       ! 0.45 ! 0.56 !
    v       ! 0.46 ! 0.55 !
    m       ! 0.43 ! 0.44 !
    ME      ! 0.73 ! 0.81 !
    Me      ! 0.68 ! 0.75 !
    M       ! 0.73 ! 0.73 !
    E       ! 0.69 ! 0.66 !
    S       ! 0.72 ! 0.76 !
    w       ! 0.50 ! 0.64 !
    f       ! 0.44 ! 0.59 !
   ------------------------

Table 4. Rotated factor loadings and eigenvalues for 10 scales and subscales of four chronobiological questionnaires (Left - Russian version, right - English version)
---------------------------------------
FACTOR:  1    2    3  !   1    2   3 !
Scale  --------------------------------
   r   !     .737     ! .300 .776     !
   v   !          .869!           .820!
   m   ! .634         ! .700          !
   ME  ! .857         ! .916          !
   Me  !-.801         !-.854          !
   M   !-.781         !-.737      .424!
   E   !-.597    -.515!-.715     -.331!
   S   !    -.742     !     -.697     !
   w   !    -.413-.662!     -.265-.642!
   f   !    -.546     !     -.750     !
----------------------------------------
EIGEN- !2.93 1.78 1.28! 3.37 1.69 1.42!
VALUE  !              !               !
% TVE  !29.3 47.1 60.0! 33.8 50.7 64.9!
---------------------------------------
Note. Factors were rotated (varimax rotation). Three-factor solutions.  Factor loadings < 0.25 are omitted in the Table. % TVE - percent of total variance explained. 1 factor - 0.93; 2 - 0.90; 3 - 0.84

Table 5. Rotated factor loadings,communalities and eigenvalues for tetrads of the sleep-wake pattern assessment questionnaire. Left - a total sample (4126 respondents; Putilov, 1993), center - Russian version, right - English version
   --------------------------------------------------------------------------
    FACTOR:   1    2    3  !   1    2    3  !   1    2    3 ! (As originally! 
    SCALE:    S    M    E  !   M    S    E  !   M    S    E ! suggested)tet-!
    S-SCALE:  f    w    w  !   w    f    w  !:  w    f    w ! rad belongs to!
    -------------------------------------------------------------------------
    TETRAD                 !                !               ! SCALE/SUBSCALE!
    s3    ! .760           !      .574      !      .708     !     S         !
    s2    ! .854           !      .777      !      .601     !     S         !
    s1    ! .803           !      .807      !      .791     !     S         !
    f     ! .437           !      .318      !      .514     !     S/f       !
    m1    !      .675      ! .605           ! .538          !     M         !
    m2    !      .749      ! .771           ! .751          !     M         !
    m3    !      .824      ! .781           ! .832          !     M         !
    w     !     -.463 .497 !-.253      .671 !-.537      .607!     E/w       !
    e2    !           .856 !           .750 !           .794!     E         ! 
    e1    !           .818 !           .724 !           .613!     E         !
   --------------------------------------------------------------------------
    EIGEN-! 2.31 1.95 1.71 ! 2.36 1.67 1.27 ! 2.27 1.92 1.27!               !
    VALUE !                !                !               !               !
    % TVE ! 28.1 46.4 60.1 ! 23.6 40.3 53.0 ! 22.8 42.0 54.7!               !
   --------------------------------------------------------------------------
Note. Factors were rotated obliquely (direct oblimin rotation for a total sample, varimax - for others). Three-factor solutions. Factor loadings < 0.25 are omitted in the Table. % TVE - percent of total variance explained. 1 factor - 0.87; 2 - 0.86; 3 - 0.91