Experiences of life disruption, threat, distress, or adversity can lead to positively evaluated “growth” (Tedeschi and Calhoun, 1995). It has been observed for centuries that benefit finding and posttraumatic growth (PTG) can follow the occurrence of traumatic events including accidents, warfare, death of a loved one, and cancer diagnosis and treatment (Stanton, 2010).
Benefit finding and growth represent a fundamental restorative principle of homeostasis that is continually active towards the achievement of stability, equilibrium and well-being. Adaptation to any life-threatening illness, such as cancer, is facilitated by homeostasis systems that include the drive to find meaning, exert mastery or control over the experience, and bolster self-esteem. Growth and benefit-finding are frequently reported by cancer survivors as they gain awareness of their illness, its treatment and prognosis.
Measurement of PTG
The theoretical model of PTG proposed by Tedeschi and Calhoun suggests growth occurs in different ways. Developing new relationships, finding new appreciation for life, new meanings in life, discovering personal strength, experiencing spiritual change, and realizing new opportunities are all possibilities. The experiences of benefit finding and growth are undeniable. The methods and measurements used for their study, however, raise more questions than answers.
Among cancer populations, reported prevalence rates of perceived PTG range from 53 to 90% and vary according to the type of cancer, time since diagnosis, heterogeneity and ethnicity of the sample, choice of measurement, and many personal factors (Coroiu et al., 2016). Posttraumatic growth is measured using scales such as “The Posttraumatic Growth Inventory” (PTGI), a 21-item measure of positive change following a traumatic or stressful event (Tedeschi and Calhoun, 1996). Respondents rate the degree to which positive change had occurred in their life “as a result of having cancer.” A total PTGI score and five subscale scores (New Possibilities, Relating to Others, Personal Strength, Spiritual Change, and Appreciation of Life) are calculated.
What the Critics Say
Critics have been less than enthusiastic about measuring PGI in this manner. James Coyne and Howard Tennen (2010) argue that: “Every PTG scale asks participants to rate how much they have changed on each scale item as the result of the crisis they faced. Thus, a respondent must: (a) evaluate her/his current standing on the dimension described in the item, e.g., a sense of closeness to others; (b) recall her/his previous standing on the same dimension; (c) compare the current and previous standings; (d) assess the degree of change; and (e) determine how much of that change can be attributed to the stressful encounter. Psychological science, which purportedly guides positive psychology, tells us that people cannot accurately generate or manipulate the information required to faithfully report trauma- or stress-related growth (or to report benefits) that results from threatening encounters…The psychological literature demonstrates consistently that people are unable to recollect personal change accurately” (Coyne and Tennen, 2010, p. 23).
The five steps a-e certainly are a tall order, and it seems highly doubtful that anybody could achieve them with any accuracy. It seems naïve to analyse numbers that research participants place on scales from the PTGI as though they are valid indices of ‘post-traumatic growth’ when no attempt is made to validate these measures. In spite of these criticisms, many studies have been conducted using the PTGI scale.
Quite rightly, Coyne and Tennen (2010) have damned the flawed methods and measures concerning PTG: “We are at a loss to explain why positive psychology investigators continue to endorse the flawed conceptualization and measurement of personal growth following adversity. Despite Peterson’s …warning that the credibility of positive psychology’s claim to science demands close attention to the evidence, post-traumatic growth—a construct that has now generated hundreds of articles—continues to be studied with flawed methods and a disregard for the evidence generated by psychological science. It is this same pattern of disregard that has encouraged extravagant claims regarding the health benefits of positive psychological states among individuals living with cancer” (p. 24).
As long as psychologists use shoddy methods, invalid measures and draw quack conclusions, they will not be taken seriously by outsiders.
Based on a section of: David F Marks et al. (2018) Health Psychology. Theory, Research & Practice (5th ed.) SAGE Publications Ltd.