The instrument used for assessing bipolar disorder is the Cognitive Complaint in Bipolar Disorder Rating Assessment (COBRA).
To assess the condition of the patients with bipolar disorder the COBRA is used. As cited in Toyoshima et al. (2017), “The Cognitive Complaints in Bipolar Disorder Rating Assessment (COBRA) is a self-reporting rating scale developed by the Bipolar Disorder Program at the Hospital Clinic of Barcelona that assesses subjective cognitive impairment in daily life activities experienced by patients with bipolar disorder” (p. 5). It was found to be correlated partially with the assessment of executive functions and memory. The COBRA has 16 items with the help of which patients can report evaluation of cognitive dysfunction that relates to processing speed, verbal learning, function, mental tracking, and working memory (Toyoshima et al., 2017). A 4-point scale is used to rate the items, from zero to four, where zero corresponds to the absence of subjective complaints, and four corresponds to the constant experience of individual complaints. The total score is calculated, so the higher the score, the higher the complaint level.
Types of Reliability
Reliability is a degree to which the results of the experiment or study can be replicated. The absence of reliability may arise from the inconsistency in instruments of measurement or observers or measured attributes (Bolarinwa, 2015). It is important to note that reliability refers to the scores of the test, not people, so that it is impossible to say that observers of the experiment were reliable.
Test-retest reliability refers to the results of the study that show consistency when testing is repeated. The test is used to assess stability that involves measuring instruments, for example, questionnaires on the same individual obtain the same result as in the previous measurement (Bolarinwa, 2015). It is the most common method of reliability testing. The results are estimated at a 1x rate and 2x rate with the following assumptions. Firstly, the testing characteristics should not change over time, which is called the “testing effect.” Secondly, the period should be long enough to ensure that the memory of the previous test’s scores does not affect the result of the current analysis. In the study by Toyoshima et al. (2017), 35 patients in remission were assessed for test-retest reliability. This means that these patients were evaluated with COBRA and then 2-4 weeks after the first assessment to check for the consistency in 16 items. One disadvantage and what researchers have to take into account is that respondents become familiar with the questions and might answer relying on their memories, making the results unreliable.
Another type of reliability is alternate form reliability, which refers to the similarity in the results of two or more measurement instruments such as different questionnaires. Questions in such surveys are reworded so that two similar but not identical forms are generated (Bolarinwa, 2015). The more correlated the results, the more equivalent they are and thus more reliable. The assessments occur at the same time or with some delay. In practice, this type of reliability is rarely used as it is challenging to ensure the parallelism of the tests. The example of alternate form reliability regarding COBRA is different versions of this assessment, Spanish and Japanese (Bolarinwa, 2015). The analysis can be performed using both of the versions and then compared for consistency.
Types of Validity
Validity describes the level to which an instrument measures what it aims to measure. The efficacy of the survey can be established by experts who assess theoretical constructs (Bolarinwa, 2015). This is called representational or translational validity, and it includes face validity. Another type of validity is when the questionnaire is compared to another survey to assess how good one measure is related to the external criterion (Bolarinwa, 2015). The example of this form is constructed validity.
Face validity is when a researcher or individual who is an expert in the research subject assesses a questionnaire and concludes that it measures a trait or characteristic of interest. According to Bolarinwa (2015), “Face validity involves the expert looking at the items in the questionnaire and agreeing that the test is a valid measure of the concept being measured just on its face. This means that they evaluate whether each of the measuring items matches any given conceptual domain of the concept” (p. 196). It is considered soft, casual, and many researchers think that it is not an active measure. For example, the COBRA seems to have a high level of face validity because it measures what it aims to measure, the cognitive impairments in patients who have bipolar disorder.
Construct validity is a level to which a research instrument measures theoretical contrast or trait that it aims to measure. It measures how valid and appropriate the tool or scale is when used in practice (Bolarinwa, 2015). It is valuable in social sciences because there are numerous subjective concepts. The example is a measurement of intelligence, human brain, proficiency, or level of emotions. Construct validity is related to the COBRA as the latter assesses memory and cognitive functioning, which are abstract notions.
Bolarinwa, O. A. (2015). Principles and methods of validity and reliability testing of questionnaires used in social and health science researches. Nigerian Postgraduate Medical Journal, 22(4), 195-201.
Toyoshima, K., Fujii, Y., Mitsui, N., Kako, Y., Asakura, S., Martinez-Aran, A., …& Kusumi, I. (2017). Validity and reliability of the cognitive complaints in bipolar disorder rating assessment (cobra) in Japanese patients with bipolar disorder. Psychiatry Research, 254, 85– 89.