Individual Change Scores Research Articles

The NIH Minimal Dataset for Chronic Low Back Pain: Responsiveness and Minimal Clinically Important Change.

Prospective cohort study. To analyze responsiveness and minimal clinically important change (MCIC) of the US National Institutes of Health (NIH) minimal dataset for chronic low back pain (CLBP). The NIH minimal dataset is a 40-item questionnaire developed to increase use of standardized definitions and measures for CLBP. Longitudinal validity of the total minimal dataset and the subscale Impact Stratification are unknown. Total outcome scores on the NIH minimal dataset, Dutch Language Version, were calculated ranging from 0 to 100 points with higher scores representing worse functioning. Responsiveness and MCIC were determined with an anchor-based method, calculating the area under the receiver operating characteristics (ROC) curve (AUC) and by determining the optimal cut-off point. Smallest detectable change (SDC) was calculated as a parameter of measurement error. In total 223 patients with CLBP were included. Mean total score on the NIH minimal dataset was 44 ± 14 points at baseline. The total outcome score was responsive to change with an AUC of 0.84. MCIC was 14 points with a sensitivity of 72% and specificity 82%, and SDC was 23 points. Mean total score on Impact Stratification (scale 8-50) was 34.4 ± 7.4 points at baseline, with an AUC of 0.91, an MCIC of 7.5 with a sensitivity 96% of and specificity of 78%, and an SDC of 14 points. The longitudinal validity of the NIH minimal dataset is adequate. An improvement of 14 points in total outcome score and 7.5 points in Impact Stratification can be interpreted as clinically important in individual patients. However, MCIC depends on baseline values and the method that is chosen to determine the optimal cut-off point. Furthermore, measurement error is larger than the MCIC. This means that individual change scores should be interpreted with caution. 2.

Visuospatial learning and memory in children pre- and posttemporal lobe resection: Patterns of localization and lateralization

In children with epilepsy, the impact of surgery including or sparing the mesial temporal lobes (TLs) on visuospatial memory has not been thoroughly investigated, and a clear pattern of hemispheric lateralization has not been observed. The primary aim of this study was to examine visuospatial learning and memory outcomes in children with epilepsy prior to and one year after surgical excision, to determine whether outcomes differed as a function of the localization and lateralization of surgical excisions. Forty-six children who underwent unilateral TL surgery with sparing of the mesial structures (TL group, N = 21, 16 left) or including mesial structures (TL + M group, N = 25 children, 12 left) were retrospectively recruited. Outcomes on the Children's Memory Scale (CMS) Dot Locations subtest (learning, immediate, and delayed recall scores) were examined prior to and following epilepsy surgery. Results revealed significantly reduced visuospatial memory (delayed recall) in the TL + M compared with the TL group after surgery. Despite this significant postoperative difference, there was no significant change in learning, immediate, or delayed recall scores in either group. However, inspection of individual change scores showed that fewer children in the TL + M group improved in delayed recall after surgery (7.2%) compared with children in the TL group (30%) whereas a similar proportion of children in the TL + M (30.4%) and TL (23.3%) groups showed a decline. There were no significant differences in learning or memory scores as a function of seizure laterality before or after surgery and no differences in change over time. Seizure outcome, age at surgery, age at seizure onset, and percentage life with epilepsy were not related to visuospatial learning or memory outcomes; however, greater number of antiepileptic drugs (AEDs) following surgery was related to poorer visuospatial memory (delayed recall) in the TL + M group. In summary, the results show that visuospatial learning and memory performance do not seem to show a significant decline following TL resections in childhood, regardless of whether or not surgery includes the mesial TL and involves the left or right hemisphere. However, although mesial TL excisions might not result in a deficit in visuospatial memory, they may hinder progressions made after surgery. Further research is needed to examine how resection of the mesial TL (alone or in combination with lateral TL structures) affects visuospatial memory outcomes in children, as well as to investigate the degree to which other treatment factors, such as medication, may affect visual memory outcomes.

Interpreting Meaningful Change in the Distance Walked in the 10-Metre ISWT in Cardiac Rehabilitation

The interpretability of change in exercise test scores is an important measurement property. This study aimed to provide a framework for the interpretation of individual change scores of the 10metre incremental shuttle walk test (ISWT) in cardiac rehabilitation. In a quantitative pre-post design study, 52 patients who were referred to a hospital outpatient department for cardiac rehabilitation participated in this study. Participants completed two ISWTs prior to cardiac rehabilitation. Post cardiac rehabilitation, participants completed a global rating of change score and two ISWTs. Change scores were analysed for smallest detectable change (SDC) and minimum important change (MIC). The SDC for an individual was 47 metres. The predicted MIC for participants to report an improvement ranged from 70 to 92 metres. The predicted MIC for participants who did not report a deterioration in the global rating of change (i.e., those who reported unchanged or improved) ranged from 16 to 42 metres. The MIC for patients who report any improvement in physical fitness and functional capacity is 70 metres. These results suggest that over an 8-week program, patients would need to improve by at least seven shuttles to perceive an improvement in their physical fitness and functional capacity. Patients with small increases in the 10-metre ISWT distance may still report deterioration in their physical fitness and functional capacity.

How does patient-rated outcome change over time following the surgical treatment of degenerative disorders of the thoracolumbar spine?

Patient-rated measures are considered the gold standard for assessing the outcome of spine surgery, but there is no consensus on the appropriate timing of follow-up. Journals often demand a minimum 2-year follow-up, but the indiscriminate application of this principle may not be warranted. We examined the course of change in patient outcomes up to 5years after surgery for degenerative spinal disorders. The data were evaluated from 4287 consecutive patients (2287 women, 2000 men; aged 62±15years) with degenerative disorders of the thoracolumbar spine, undergoing first-time surgery at the given level between 01/01/2005 and 31/12/2011. The Core Outcome Measures Index (COMI; scored 0-10) was completed by 4012 (94%) patients preoperatively, 4008 (93%) at 3-month follow-up, 3897 (91%) at 1-year follow-up, 3736 (87%) at 2-year follow-up, and 3387 (79%) at 5-year follow-up. 2959 (69%) completed the COMI at all five time-points. The individual COMI change scores from preoperatively to the various follow-up time-points showed significant correlations ranging from r=0.50 (for change scores at the earliest vs the latest follow-up) to r=0.75 (for change scores after 12- vs 24-month follow-up). Concordance with respect to whether the minimum clinically important change score was achieved at consecutive time-points was also good (70-82%). COMI decreased significantly (p<0.05) from preop to 3months (by 3.6±2.8 points) and from 3 to 12months (by 0.3±2.4 points), then levelled off up to 5years (0.04-0.05 point change; p>0.05). The course of change up to 12months differed slightly (p<0.05) depending on pathology/whether fusion was carried out. For patients undergoing simple decompression, 3-month follow-up was sufficient; those undergoing fusion continued to show further slight but significant change up to 12months. Stable group mean COMI scores were observed for all patients from 12months postoperatively onwards. The early postoperative results appeared to herald the longer term outcome. As such, a 'wait and see policy' in patients with a poor initial outcome at 3months is not advocated. The insistence on a 2-year follow-up could result in a failure to intervene early to achieve better long-term outcomes.

The Interprofessional Collaborative Competency Attainment Survey (ICCAS): A replication validation study

ABSTRACTThis study replicates a validation of the Interprofessional Collaboration Competency Attainment Survey (ICCAS), a 20-item self-report instrument designed to assess behaviours associated with patient-centred, team-based, collaborative care. We appraised the content validity of the ICCAS for a foundation course in interprofessional collaboration, investigated its internal (factor) structure and concurrent validity, and compared results with those obtained previously by ICCAS authors. Self-assessed competency ratings were obtained from a broad spectrum of pre-licensure, health professions students (n = 785) using a retrospective, pre-/post-design. Moderate to large effect sizes emerged for 16 of 20 items. Largest effects (1.01, 0.94) were for competencies emphasized in the course; the smallest effect (0.35) was for an area not directly taught. Positive correlations were seen between all individual item change scores and a separate item assessing overall change, and item-total correlations were moderate to strong. Exploratory factor analysis was used to understand the interrelationship of ICCAS items. Principal component analysis identified a single factor (Cronbach’s alpha = 0.96) accounting for 85% of the total variance—slightly higher than the 73% reported previously. Findings suggest strong overlaps in the proposed constructs being assessed; use of a total average score is justifiable for assessment and evaluation.

Narrative Medicine Workshops for Obstetrics and Gynecology Residents and Association With Burnout Measures.

To determine whether a workshop Narrative Medicine curriculum can improve burnout among obstetrics and gynecology residents. A Narrative Medicine curriculum was conducted at three obstetrics and gynecology training programs. An explanatory research design examined correlation between Narrative Medicine attendance and changes in survey responses. Residents completed a pretest and 1-year posttest survey that included validated measures of burnout and empathy. A within-participants design used baseline pretest scores as an internal control and measured changes in individual scores. The primary outcome of the study was change in burnout rates. Mann-Whitney U and Kruskal-Wallis tests were used to analyze the data. A total of 66 residents at three institutions participated in the Narrative Medicine curriculum. Of those, 54 (81%) enrolled in the study by completing any part of the surveys, and 43 (80%) of those enrolled had complete data for analysis. Burnout was high on all Maslach Burnout Inventory subscales and increased over 1 year. Participants with high Narrative Medicine attendance had decreased burnout on the Emotional Exhaustion subscale (-4.1 [±8.1]) points compared with an increase of 0.5 (±6.0) for low-attendance participants (U=134, P=.02, d=0.65). Lower self-care ratings were associated with improved Personal Accomplishment (+0.5 [±5.0]) compared with +2.0 (±2.7), U=84, P=.01]. Other characteristics did not significantly correlate with burnout or empathy. Burnout was high and worsened over time among obstetrics and gynecology residents in these three programs. Higher attendance at Narrative Medicine workshops was associated with improved Emotional Exhaustion.

Changing depressive symptoms following percutaneous coronary intervention, clustering and effect on adherence – The THORESCI study

BackgroundDepressive symptom dimensions may have a differential effect on cardiac prognosis. It is yet unknown whether and how depressive symptoms change together over time and how this may affect disease progression. We examined the clustering of changing depressive symptoms over the first 6 months after percutaneous coronary intervention (PCI), and examined the influence of the change profile on the predictive value of depression for treatment adherence at 6 months post-PCI. MethodsPCI patients (N=219, age: 62±15, 20% women) reported on depressive symptoms (PHQ-9, BDI; 30 symptoms) and adherence (MOS-GAS) at 1 and 6 months post-PCI. Principal component analysis (PCA) was performed on the individual symptom change scores. Multivariable linear regression examined the role of change profiles in predicting general treatment adherence, while adjusting for demographic and clinical characteristics. ResultsFour change-factors emerged from PCA. One somatic-affective change-factor (10 symptoms), two cognitive-affective change-factors (6 general cognitive-affective and 7 severe cognitive symptoms) and one mixed factor were identified. We extracted 5 symptom change profiles. Linear regression showed the moderating role of the change profiles. In patients reporting a net increase in depressive symptoms, higher cognitive affective symptoms (β=−.46, p=.001) and higher somatic-affective symptoms (β=−.29; p=.044) were associated with worse general adherence. DiscussionFour distinct depressive symptom change-factors were identified that moderated the association of somatic-affective and cognitive-affective depressive symptom levels with general treatment adherence. This is of clinical importance as not only current symptoms, but also symptom change over the preceding months may be important to consider in screening and risk prediction.

Stability and change of basic personal values in early adulthood: An 8-year longitudinal study

We examined four types of stability and change in values during young adulthood. 270 respondents (aged 20–28, 54% female) completed the Portrait Values Questionnaire at three time points, separated by 4years. Rank-order stability coefficients of the 10 values averaged 0.69 (T1-T2) and 0.77 (T2-T3). The mean importance of conservation, self-transcendence, and power values increased over time, the mean importance of achievement values decreased, and openness to change values remained stable. For 75% of respondents, the correlations of the within-person value hierarchies exceeded 0.45 from T1 to T2 and 0.61 from T2 to T3. Correlations among individual change scores for the 10 values formed coherent patterns of value change that mirror the circular structure of Schwartz’s theory.

Piloting an email-based resource package for job seekers with multiple sclerosis

Purpose: Media-based rehabilitation provides a powerful opportunity to examine vocational behaviors in the disability sector. However, this research is preliminary at best. This paper reports pilot data. Method: Eighteen adults with multiple sclerosis (MS) accessed an email-delivered, resource-based package, Work and MS. Pre- and post-access vocational self-efficacy and identity (Job-Procurement Self Efficacy Scale, My Vocational Situation Scale- primary outcomes), life orientation and depressed mood (Life Orientation Test – revised and Patient Health Questionnaire-9 – secondary outcomes) were assessed. Pre- and post-change scores were examined with Wilcoxon signed ranks tests and Hedges g effect sizes with associated 95% confidence intervals. Reliable change analyses were additionally calculated to determine the clinical significance of individual change scores. Results: Significant and positive effects were reported for vocational self-efficacy, identity, and optimism. Reliable change scores in one or more of these key outcomes were reported by 30% of the sample. Satisfaction with the content and delivery of the email-based intervention was also noted. Conclusions: Preliminary evidence suggests that Work and MS can help to promote vocational goals, interests and strengths among job seekers with a disability by providing a set of tools, information and linkages relating to vocational pursuits and career development. Replication with a randomized control design is indicated.Implications for RehabilitationResearch indicates a high unemployment rate among working-age adults with MS.A combination of disease-specific, psychological, programmatic and societal variables contribute to employment instability in this group.This pilot study demonstrates that an e-mail-based resource package, Work and MS, provides an innovative and feasible option for promoting consumer engagement with vocational services and, potentially, improving vocational outcomes.Work and MS has potential applicability to other disability groups.

APSAD 2015 Conference, 8-11 November 2015, Perth, Western Australia.

Design and Methods: Participants were 757 PWID enrolled in the Melbourne Injecting Drug User Cohort Study. We used gender-stratified linear models with fixed effects for each participant to examine correlates of change in individual scores on the Personal Wellbeing Index (PWI) over time. Further linear regression of adjusted PWI scores was used to measure correlations between demographic variables.

Reduction in delta activity predicted improved negative affect in Major Depressive Disorder

While prior research has demonstrated a paradoxical antidepressant effect of slow-wave disruption (SWD), the specific dimensions of depression affected is still unclear. The current study aimed to extend this research by utilizing a dimensional approach in examining the antidepressant effects of SWD. Of particular interest is the affective dimension, as negative affect in depression is arguably the most salient characteristic of depression. This sample included 16 individuals with depression (10 female) recruited from the community. Participants slept in the lab for three nights (adaptation, baseline night, and SWD) with polysomnography, and completed measures of negative affect and depression severity the following morning. Results show that reduction in delta power was linearly associated with improved negative affect. Comparison of individual change scores revealed that half of the individuals showed improved negative affect, which is comparable to the reported 40–60% antidepressant response rate to sleep deprivation. Results suggest that vulnerability in the sleep homeostatic system may be a contributing individual differences factor in response to slow-wave disruption in depression.

The Overclaiming Questionnaire: A good way to measure faking?

We evaluated the validity of the Overclaiming Questionnaire (OCQ) as a measure of job applicants’ faking of personality tests. We assessed whether the OCQ (a) converged with an established measure of applicant faking, Residualized Individual Change Scores (RICSs); (b) predicted admission of faking and faking tendencies (Faking Frequency, Minimizing Weaknesses, Exaggerating Strengths, and Complete Misrepresentation); and, (c) predicted the aforementioned measures as strongly as RICSs did. First, 261 participants were instructed to respond honesty to an extraversion measure. Next, in a mock job application, they filled out the extraversion measure again, as well as the OCQ. The OCQ only weakly predicted RICSs (r=.17), Faking Admission (r=.18), and Faking Frequency (r=.15), and it failed to correlate significantly with Minimizing Weaknesses, Exaggerating Strengths, and Complete Misrepresentation. Moreover, the OCQ performed significantly worse than RICS in predicting Faking Admission, Faking Frequency, Minimizing Weaknesses, Exaggerating Strengths, and Complete Misrepresentation. We urge caution in using the current version of the OCQ to measure faking, but speculate that the innovative approach taken in the OCQ might be more effectively exploited if the OCQ content were tailored to the specific job that applicants are being tested for.

Quality of Life After Laparoscopic Adjustable Gastric Banding (LAP-BAND): APEX Interim 3-Year Analysis

Background: Obesity is often associated with diminished health-related quality of life (HRQOL), but significant gains in HRQOL have been observed after bariatric surgery. Laparoscopic adjustable gastric banding has been established as a safe, effective treatment to reduce weight in patients with obesity. This report summarizes interim 3-year changes in HRQOL and body weight, as well as safety postimplantation of the LAP-BAND AP (LBAP) system. Methods: The LAP-BAND AP EXperience (APEX) trial, an ongoing, prospective, 5-year, open-label study, assessed changes in HRQOL (Obesity and Weight-Loss Quality of Life [OWLQOL] questionnaire) and body weight, and safety after placement of LBAP. This interim analysis represents patients with evaluable OWLQOL data at baseline and at 3 years (n = 183). Results: The OWLQOL total score and individual scores significantly improved within 6 months post-LBAP and continued to improve during a 3 year period (P < 0.0001, both). Total score improved from 71.0 to 34.0 (mean improvement from baseline, 52%; range, 18%–65%); mean change in individual scores was −2.2 (range, −0.7 to −3.0). Percent weight loss was maintained through 3 years (19.4%; n = 174). Improvement in OWLQOL was associated with percent weight loss at 3 years (r = −0.5407; P < 0.0001). Revisions and explants were performed in 7 (3.8%) and 20 (10.9%) out of 183 patients, respectively. Conclusions: Meaningful improvement in quality of life occurred through clinically significant weight loss after LBAP placement, extending throughout the 3 years of this analysis.

Increased intelligence is a myth (so far)

Increased intelligence is a myth (so far)

Assessment of knowledge of vincristine toxicities in outpatient pediatric hematology/oncology nurses: An educational intervention.

231 Background: Vincristine (VCR) is a chemotherapeutic agent with a unique neurological side effect profile and is integral to the treatment of many pediatric hematological and solid malignancies. Side effects requiring VCR dose modification include peripheral neuropathies, intestinal ileus, cranial nerve abnormalities, hyponatremia and seizures. In our institution, orders for weekly VCR are written in advance by oncologists and administered by outpatient nurses independent of a provider physical examination. We sought to increase knowledge of VCR toxicities and improve pre-chemotherapy evaluation skills among outpatient Hematology/Oncology (Hem/Onc) nurses. Methods: A 23-question written quiz was given as a pre-test to 14 outpatient Hem/Onc nurses to assess their fund of knowledge regarding VCR toxicities. An educational intervention was then provided to the cohort as a lecture by a Hem/Onc fellow physician. The lecture was followed by the same quiz given as post-test to the nurses. Individual participant and group scores were tabulated comparing pre and post-test responses to assess improvement in identification and recognition of VCR toxicities. Results: 12/14 nurses demonstrated improvement in their fund of knowledge regarding VCR side effects (mean change in individual scores + 4.7). As a group, mean scores increased from 15.2 to 18/23 (the two-sample paired t-test was significant with a two-tailed p&lt;0.005). Conclusions: An educational intervention significantly improved outpatient Hem/Onc nurses fund of knowledge regarding identification and evaluation of VCR toxicities. Future objectives include follow-up evaluation of retention of knowledge of VCR side effects and incorporating a VCR toxicity checklist into the electronic medical record outpatient nursing note.

Prodromal functioning of migraine patients relative to their interictal state--an ecological momentary assessment study.

Smartphones were used in an online Ecological Momentary Assessment (EMA) design to test prodromal functioning relative to the interictal state in migraine patients. Eighty-seven participants completed an electronic diary 4 times daily during 3-6 weeks to monitor their migraine attacks. Twice daily the diary additionally included 16 multi-answer questions covering physical symptoms (30 items), cognitive-affective functioning (25 items) and external factors (25 items). Eight clustered prodromal features were identified in the current study: sensory sensitivity, pain/stiffness, fatigue, cognitive functioning, positive affect, negative affect, effort spent and stressors encountered. Per feature, individual change scores with interictal control days - excluding 24-hour post-attack recovery - were computed for six 12-hour pre-attack time windows covering three prodromal days. Linear mixed model (fixed-effect) analysis established significant increases in sensory sensitivity, pain/stiffness and fatigue, and a tendency for increased negative affect, in the 12 hours prior to the attack. Positive affect and cognitive functioning were impaired both in the 25-36 hour and - more strongly - in the 12-hour time window before the attack. No effects were found for effort spent and stressors encountered. Exploratory (random effect) analysis revealed significant individual differences in the change scores in sensory sensitivity, pain/stiffness, fatigue and negative affect. It is concluded that the prodromal change in migraine - relative to interictal functioning - predominantly exists within the last 12 hours before attack onset. Individual diversity is large, however. Future research should zoom in to identify prodrome development within the 12 pre-attack hours as well as to isolate individual patterns.

Does intra-individual change predict offender recidivism? Searching for the Holy Grail in assessing offender change

Offender rehabilitation effectively reduces recidivism for treatment groups compared to control groups, but there is less evidence demonstrating that intra-individual changes are related to reductions in risk. We review and critique academic and government literature linking individual change scores to recidivism, focusing on three key treatment domains: cognition, violence, and substance misuse. Database searches identified 378 studies measuring change, but only 53 studies yielding 49 explicit tests of the relationship between intra-individual change scores and recidivism outcome. Of the 49 available tests, 26 effect sizes (53.1%) were significant, ranging from small (d = 0.06) to large (d = 1.48). Across all domains, change variables significantly related to recidivism included known dynamic risk factors: antisocial attitudes, antisocial beliefs, antisocial associates, antisocial personality, social support, and substance misuse. Two additional findings centered on changes in negative emotion and successful treatment process. This review further suggests there is a need to utilize better measurement strategies and more sophisticated constructs. Additional practical, theoretical, and methodological implications are discussed.

Environmental stress alters genetic regulation of novelty seeking in vervet monkeys

Considerable attention has been paid to identifying genetic influences and gene–environment interactions that increase vulnerability to environmental stressors, with promising but inconsistent results. A nonhuman primate model is presented here that allows assessment of genetic influences in response to a stressful life event for a behavioural trait with relevance for psychopathology. Genetic and environmental influences on free-choice novelty seeking behaviour were assessed in a pedigreed colony of vervet monkeys before and after relocation from a low stress to a higher stress environment. Heritability of novelty seeking scores, and genetic correlations within and between environments were conducted using variance components analysis. The results showed that novelty seeking was markedly inhibited in the higher stress environment, with effects persisting across a 2-year period for adults but not for juveniles. There were significant genetic contributions to novelty seeking scores in each year (h2 = 0.35–0.43), with high genetic correlations within each environment (rhoG > 0.80) and a lower genetic correlation (rhoG = 0.35, non-significant) between environments. There were also significant genetic contributions to individual change scores from before to after the move (h2 = 0.48). These results indicate that genetic regulation of novelty seeking was modified by the level of environmental stress, and they support a role for gene–environment interactions in a behavioural trait with relevance for mental health.

Intra-individual changes in anxiety and depression during 12-month follow-up in percutaneous coronary intervention patients

Only a paucity of studies focused on intra-individual changes in anxiety and depression over time and its correlates in cardiac patients, which may contribute to the identification of high-risk patients and point to targets for intervention. We examined changes in anxiety and depression over a 12-month period and the demographic and clinical correlates of change scores using an intra-individual approach in patients treated with percutaneous coronary intervention (PCI). Consecutive PCI patients (N=715) completed the Hospital Anxiety and Depression Scale (HADS) at baseline and at 12 months post-PCI. Individual change scores were calculated and in secondary analysis, three categories of change were identified (i.e., stable, improved, and deteriorated anxiety or depression). The mean individual change was -.16 (± 3.0) for anxiety and -.02 (± 2.8) for depression. In linear regression analysis, baseline anxiety levels (B = -.25, 95%CI[-.30 to -.20], p = <.001) and baseline depression levels (B = -.28, 95%CI[-.33 to -.22], p =< .001) were significant correlates of individual change scores. Secondary analysis showed that anxiety remained stable in 76.4% (546/715) of patients, while depression remained stable in 81.4% (582/715) of patients. The findings of the current study showed that levels of anxiety and depression remained stable in the majority of PCI patients from the index PCI to 12 months post-PCI. Future studies using an intra-individual approach are warranted to further examine individual changes in anxiety and depression over time in CAD, and PCI in particular, as a means to bridge the gap between research and clinical practice.

Changing your mind about seeing a brand that you never saw: Implications for brand attitudes

Two field experiments examine the attitudinal consequences of consumers changing their minds about previously seeing brands when in fact they have not. In the first study, an increase in false brand awareness, holding brand exposure constant, is found to result in more favorable brand attitudes. In the second study, changes in false brand awareness were found to mediate the development of defensive thoughts in which respondents self-justify changing their minds. Defensive thoughts, in turn, mediate the development of brand attitudes. The results suggest that simple changes in one's subjective probability of previously seeing a brand independent of actual exposure can have significant attitudinal consequences for that brand. This is due to the generation of self-justifying cognitions. Individual change scores are further found to have greater theoretical and empirical utility than static measures. © 2011 Wiley Periodicals, Inc.