This fact sheet provides professionals with answers to their
frequently asked questions about assessment.
What is the difference between a trauma exposure measure and a
PTSD measure?
The purpose of a trauma exposure measure is to identify what
traumatic events an individual has experienced; the purpose of a
PTSD measure is to determine whether the person has PTSD symptoms
related to one of the identified events. There are a variety of
trauma exposure measures. Some are very broad and assess a range
of negative life events as well as traumatic experiences. Others
have a narrower focus and only assess Criterion A traumas that
involve life threat. Similarly, there are a range of PTSD
measures that can be broad enough to include symptoms other than
those related to PTSD. There are also PTSD measures that are more
focused on the 17 PTSD symptoms needed to make a diagnosis. In
most cases, a thorough PTSD assessment involves the use of both a
broad measure and a more focused measure.
What are the main differences among PTSD measures?
PTSD measures vary in a number of ways. There are some basic
differences to consider in terms of the (1) time required to
administer the measure, (2) complexity of the format, (3) reading
level of the person to be assessed, and (4) cost of use. Format
is an import difference among measures. Measure formats range
from 17-item self-report measures with a single rating for each
item, to structured interviews with detailed inquiries about each
symptom and interviewer ratings regarding the validity of
reports. Structured interviews also differ in (1) whether they
have a single gate-keeping item, (2) the level of sophistication
for assessing each PTSD symptom, and (3) how well the ratings
reflect symptom severity and/or frequency. Although interview
measures require more interviewer training and administration
time, they result in a more comprehensive assessment of PTSD. The
right measure for a particular purpose depends on your goal. If
you want a quick screen, a self-report measure may be best.
However, if you are conducting a PTSD treatment study, you may
want a sensitive interview that assesses for frequency and
severity of symptoms.
What are the main differences among trauma exposure
measures?
Trauma exposure measures differ a great deal in length, the
range of trauma types assessed, and the degree of detailed
inquiry about each traumatic event. Many simply assess exposure
to high-magnitude stressors that could cause traumatic stress,
and others have detailed questions to follow up endorsed events.
For example, one measure may have detailed questions about
certain elements of an interpersonal violence experience, and
another measure may only require a 'yes' or
'no' to the question of whether the person was exposed
to a particular type of interpersonal violence. Some measures
have been better validated than other measures, and some differ
as to whether they assess the nature, degree, and duration of
emotional responses to the stressor.
What is the best measure for assessing PTSD symptoms?
Although we are frequently asked this question, there is no
one 'best' PTSD measure. The best measure really
depends on what you need. Some important considerations in
choosing a PTSD measure include: the time required to administer
the measure, the reading level of the population being sampled,
whether the desire is to assess symptoms related to a single
traumatic event or to assess symptoms related to multiple
traumatic events (or to assess symptoms when the trauma history
is unknown), the need for the assessment to correspond to DSM
criteria for PTSD, the psychometric strengths and weaknesses of
the measure, and the cost of using the measure. In addition, it
is important that the overall complexity and language of the
measure be appropriate to the population being sampled.
If you are looking to make a diagnosis of PTSD (rather than
simply assessing symptoms), in general, structured interviews
will yield more valid results than other types of measures. An
exception is that structured interviews that begin with a single
gate-keeping item have poor validity for particular types of
traumatic experiences. Also, structured interviews with brief,
single-item, closed-ended questions for each PTSD symptom are
likely to be no more valid for making a diagnosis than
self-report measures. Lastly, the validity of a structured
interview will be greatly affected by the level of training of
the interviewer. If interviewers do not have specific training in
mental disorders, clinical assessment, traumatic stress, and
administration of the particular structured interview being used,
results of the interview may be invalid. Brief scales and
self-report measures cannot be used to establish a diagnosis of
PTSD because there is too much chance for error in responses.
How do I choose a measure to assess trauma history?
It is difficult to assess trauma history because researchers
cannot firmly establish the validity of trauma-exposure measures.
It is so difficult to determine whether trauma reports are
accurate that the validity of even the best measures has not been
very rigorously studied. That being said, it seems likely that
trauma-exposure assessments will have some validity, and their
clinical relevance makes them necessary.
In choosing a measure of trauma history or exposure, there is
generally a trade-off between the specificity of the assessed
traumatic events and the length of the assessments. Measures that
query about the widest range of potentially traumatic events, and
presumably yield the most accurate reports, will be the longest.
Measures that are quick and easy will inquire very broadly about
types of events and may 'miss' idiosyncratic traumatic
events. Thus, in choosing a trauma-exposure measure for research,
investigators will typically need to weigh the need for a
detailed trauma-exposure assessment against the time limitations
for the administration. Another consideration is whether the
researcher is more interested in data regarding exposure to
potentially traumatic (or high-magnitude) stressors or regarding
exposures that resulted in significant emotional responses. Only
a few measures assess the nature, degree, and duration of
emotional responses to the stressor.
How can I obtain trauma exposure and PTSD assessment
measures?
The American Psychological Association's ethical guidelines on
psychological test instruments require advanced graduate-level
training in the administration and interpretation of
psychodiagnostic assessment instruments. Thus, we are not able to
distribute measures to people who do not hold at least a master's
degree in a clinical discipline. Graduate students must have a
professor request the measure for them and use the measure under
the professor's supervision.
In the Assessment Section on our Web site, you can find
additional information about many measures, including a contact
name and address for obtaining the measure. If the measure was
developed by the National Center for PTSD, you can submit a
request form to obtain the assessment tool.
See the Assessment Section of our website for a wealth of
information about PTSD, trauma and assessment.
