THE INTERNET ENCYCLOPAEDIA OF
PERSONAL CONSTRUCT

PSYCHOLOGY



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Checking for Reversals
(Otherwise known as checking the directionality of construct relationships).

When comparing the ratings on any two sets of constructs in a Repertory Grid, it is always necessary to remember that constructs are bipolar. The two sets of ratings may be highly related, but this relationship may not be apparent unless its directionality is examined.

It is easiest to proceed by example. Take the following ratings on two simple constructs which describe a person’s food preferences. Imagine that the individual has rated 7 different foods on each of the two constructs, using a 5-point scale in each case. Follow the usual convention that the left-hand pole of each construct  anchors the “1” end of the scale, and the right-hand end of each construct anchors the “5” end of the scale.

Table 1

"1"
food 1
food 2
food 3
food 4
food 5
food 6
food 7
"5"
Nice
5
3
1
4
2
3
5
Nasty
Sweet
1
2
5
2
4
3
1
Savoury


Now compute a simple Sum of Differences score, taking the absolute difference between the ratings given to each element on the two constructs and summing across: (5-1) + (3-2) + (5-1)…  (absolute difference, remember),,, + (4-2) + (4-2) … (another absolute difference)… + (3-3) + (5-1). Which equals 17. Rather a large sum of differences, given that the maximum possible difference for 7 elements rated on a 5-point scale is 7 x 4 = 28! One may be tempted to conclude that the two constructs aren’t very highly related.

But constructs are bipolar! In the second construct, the pole labelled “Sweet” is only written on the left, anchoring the “1” end of the scale, because that is the way it was written down when the construct was elicited, following the usual rule that the emergent pole is written down on the left. Suppose, however, that the emergent pole happened to be “Savoury”; in other words, that in the triadic elicitation, “Savoury” happened to be the characteristic which two of the three elements being compared had in common.

In which case, the second construct would have been written down as follows.

Table 2

"1"
food 1
food 2
food 3
food 4
food 5
food 6
food 7
"5"
Nice
5
3
1
4
2
3
5
Nasty
Savoury
5
3
1
4
2
3
5
Sweet


Look at the ratings on the second construct.

If food 1 was rated “1” on a scale that runs from “Sweet = 1” to “Savoury = 5” as in Table 1, it should of course show a rating of “5” when the scale runs from “Savoury = 1” to “Sweet = 5”: the food is construed as Sweet regardless of the directionality of the scale! Likewise, If food 4 received a rating of “2” on a scale that runs from “Sweet = 1”  to “Savoury = 5”, when the direction of the second construct is reversed so that the scale runs from “Savoury = 1” to “Sweet = 5”, it has to receive a rating of “4” if the meaning is to be preserved. And similarly for all the other element ratings.

And of course, once this is done, it is obvious in Table 2 that the two constructs are in fact maximally related. The ratings are identical with the poles written down this way round. The interviewee thinks savoury foods are nice, and sweet foods are nasty, consistently throughout, and was saying all along; yet this is not at all obvious from Table 1. But Table 1 is only as it is because of the incidental event during elicitation that led to “Sweet” being written down on the left and “Savoury” on the right.

To identify the relationship between the meanings being expressed by any two constructs, then, the similarity between the two constructs must be checked “both ways”: with the pair of constructs as they are; and with the labels of one of the constructs reversed, with its ratings being reversed to preserve the intended meaning. The value of a reversed rating is then given by subtracting the original rating from R + 1 where R is the maximum possible rating (5 on a 5-point scale, 7 on a 7-point scale, and so on).

This example uses sums of differences as its measure of similarity between constructs. The same rationale applies where the correlation coefficient is used as the measure of similarity.
 

Devi Jankowicz


Establ. 2003
Last update: 15 February 2004