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This review was authored by Barbara Anderson, Ph.D.

Introduction
Life stress has been posited as a key mechanism in the etiology and course of both psychological
and physical health outcomes. The extant evidence to date has been inconsistent and as such has
lead some researchers to suggest that stress per se does not play a major role in determining
health outcome.  Other researchers, however, have argued that different results across studies
emerge from the use of different measurement strategies.  In this respect, two research traditions
of paradigmatic status are associated with the assessment and measurement of life stress:

1. Respondent-based assessment, based on the use of self-report checklists in which
respondents are ask to identify the events they have experienced from a standard list

Hence, an important distinction between these two methods lies in the notion that for
investigator-based approaches the primary responsibility for defining and categorizing life stress
resides with the investigator not with the respondent.  In other words, the final interpretation of an
occurrence as a life event or chronic difficulty as well as the ratings assigned to that occurrence
(e.g., severity or threatfulness, independence, etc.) are made by trained researchers in conjunction
with the respondent’s self-report, omitting any information about the respondent’s actual reaction
to the occurrence.  These ratings are referred to contextual and/or objective ratings as opposed to
subjective ratings that are the product of respondent-based or self-report checklists.

In fact, a consensus is emerging in the literature that the assessment of contextual or objective
factors—the personal and psychosocial setting in which a stressor occurs—is a key consideration
in understanding the relationship between that stressor and outcome (Thoits, 1995).  In this
respect, the definition of stress as well as its effects can be viewed as a “process through which
environmental events are interpreted by people, in relation to own values and resources and
responded to psychologically, behaviorally, and biologically, (Herbert & Cohen, p. 295, 1996).
Thus, a focus on contextual factors (e.g., biographical circumstances, chronic difficulties, etc)
that elucidate the meaning of a particular stressor to a particular person within a process framework
may help to account for the variability in response to that particular stressor.

The reliance on self-report checklists makes it exceedingly difficult to evaluate context or objective
features of a particular occurrence.  For example, a checklist item such as pregnancy may be
associated with a different level of “stressfulness” for an unmarried woman with little financial or
emotional support than for a happily married woman who has planned for the event in a stable
financial position.  In contrast, investigator-based methods attempt to provide a more accurate
index of the objective severity of an occurrence by examining the context for each occurrence.
In general, though researchers need to choose measures that most likely assess their
conceptualization of life stress.

Investigator-Based Methods vs. Respondent-Based Approaches

1. Data Collection

2. Standardization/ Precision of Measurement

Advantages of Investigator-Based Measures of Life Stress Assessment
The magnitude of association between life stress and illness has been modest when
employing self-report measures.  However, in a broad range of studies, the LEDS has
achieved substantially stronger effects sizes than self-administered measures have
(see Brown & Harris, 1989).
Investigator –based methods are better suited for assessing objective features of life
circumstances, which is consistent with the stimulus-based model of psychological stress.
Checklists have demonstrated poor inter-rater reliability, low test-retest reliability, and
limited validity (see Gorman, 1995 for a review).
Investigator-based methods have developed several strategies to control for measurement
errors and biases in the identification, dating, and evaluation (e.g., severity) of life events
and chronic difficulties.
Investigator-based methods allow for greater precision in the definition of the types of
stressors (e.g., acute versus chronic, life domain, etc.) as well as precision in dating
relative to the timing of exposure and outcome.

Disadvantages of Investigator-Based Measures of Life Stress Assessment
The cost of implementation is significantly more than that cost involved in the
administration of a self-report measure:
Training is necessary.
Respondent/investigator burden in terms of time and effort for
administration is considerable.
Rating and independent review of ratings can take considerable effort and time.
There are other research considerations to take into account:
Investigator –based methods are not widely used in the literature because of cost
and training considerations so comparisons across studies remain problematic.
Extant evidence supporting their use in terms of predictive validity is limited.  Given
respondent/investigator burden they may not be suitable for large-scaled studies.

Assessment Methods Covered in this Review
This review will be divided into three sections.  In the first section, we have started with a brief
review of the LEDS since it is considered to be the “gold standard” of the investigator-based
methods of life stress assessment. A brief description of other investigator-based methods is
provided at the end of this first section.  Forthcoming in the second section will be a review of
respondent-based questionnaires of life events as well as the questionnaire assessment of daily
hassles.  The third section will review the instruments available to assess the respondent’s
perception or feelings of stress.
LEDS and Investigator-Based Methods
Respondent-Based Questionnaires (forthcoming)
Available Instruments (forthcoming)

References
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(Eds.), Handbook of health psychology. Mahwah, NJ: Lawrence Erlbaum Associates, 2001.
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Cohen S, Kessler RC, Underwood Gordon L:  Measuring stress: A guide for health and
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Gorman DM:  A review of studies comparing checklist and interview methods of data
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Katschnig H: Life events and psychiatric disorders: Controversial issues.  Cambridge:
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Kessler RC: The effects of stressful life events on depression.  Annu Rev Psychol
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McQuaid JR, Monroe SM, Roberts JE,  Kupfer DJ, Frank E: A comparison of two life stress
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