Element correlations

Description
As a measure for element similarity correlations between elements are frequently used. Note that product moment correlations as a measure of similarity are flawed as they are not invariant to construct reflection (Mackay, 1992; Bell, 2010). A correlation index invariant to construct reflection is Cohen's $$r_c$$ measure (1969), which can be calculated using the argument  rc=TRUE which is the default option.

R-Code
As a default the construct reflection invariant correlation Cohen's $$r_c$$ is calculated. > elementCor(mackay1992)

Correlation between elements

Type of correlation: Cohens's rc

1   2     3    4     5     6 Self            1   0.59  0.28 0.29 -0.61 -0.62 Ideal self     2        -0.04 -0.2 -0.38 -0.81 Mother         3              0.63  0.37 -0.43 Father         4                       0     0 Spouse         5                             0 Disliked person 6

Note how the values change when the product-moment correlation is used oinstaed of Cohen's rc. > elementCor(mackay1992, rc=F)

Correlation between elements

Type of correlation: pearson

1    2     3     4     5     6 Self            1   -0.37 -0.19  0.32 -0.75  0.96 Ideal self     2         -0.71 -0.56 -0.26  -0.3 Mother         3                0.63  0.57 -0.12 Father         4                      0.05  0.38 Spouse         5                           -0.74 Disliked person 6

To request other types of correlations:

elementCor(mackay1992, rc=F, meth="kend")   # Kendalls tau correlation elementCor(mackay1992, rc=F, meth="spear")  # Spearman rank correlation

Several arguments to format the ouput are available. elementCor(mackay1992, upper=F) elementCor(mackay1992, col.index=F, trim=6) elementCor(mackay1992, index=T, col.index=F, trim=6)

If the correlations are caclulated for as one step for further processing, the console output can be surpressed. > r <- elementCor(mackay1992, out=0) > r                Self Ideal self Mother Father Spouse Disliked person Self            1.00       0.59   0.28   0.29  -0.61           -0.62 Ideal self      0.59       1.00  -0.04  -0.20  -0.38           -0.81 Mother          0.28      -0.04   1.00   0.63   0.37           -0.43 Father          0.29      -0.20   0.63   1.00   0.00            0.00 Spouse         -0.61      -0.38   0.37   0.00   1.00            0.00 Disliked person -0.62     -0.81  -0.43   0.00   0.00            1.00

Literature

 * Bell, R. C. (2010). A note on aligning constructs. Personal Construct Theory & Practice, (7), 42-48.
 * Cohen, J. (1969). rc: A profile similarity coefficient invariant over variable reflection. Psychological Bulletin, 71(4), 281-284.
 * Mackay, N. (1992). Identification, Reflection, and Correlation: Problems in the bases of Repertory Grid measures. International Journal of Personal Construct Psychology, 5(1), 57-75.