Maudsley Obsessive-Compulsive Inventory (MOCI)

Abstract

The Maudsley Obsessive-Compulsive Inventory (MOCI) is a classic and highly influential psychological scale developed in 1977 by Hodgson and Rachman. It was designed as one of the earliest specialized self-report measures for the rapid assessment and quantification of obsessional-compulsive complaints. The inventory is crucial for measuring the severity and specific qualitative nature of symptoms associated with Obsessive-Compulsive Disorder (OCD) in both clinical and research environments.

Comprising 30 dichotomous (True/False) items, the MOCI facilitates quick screening and identifies four primary symptom dimensions: checking, washing/cleaning, slowness, and doubting. Its concise format and straightforward scoring methodology have ensured its continued relevance as a fundamental tool, particularly in behavioral modification therapies where tracking changes in specific compulsions is necessary.

Keywords

Maudsley Obsessive-Compulsive Inventory, MOCI, Obsessive-Compulsive Disorder, OCD, Obsessions, Compulsions, Checking, Washing, Self-Report Scale, Psychometrics, Clinical Assessment.

Authors

Hodgson, R. J., Rachman, S.

Purpose

The fundamental purpose of the Maudsley Obsessive-Compulsive Inventory (MOCI) is to provide an objective, standardized method for measuring the intensity and presence of specific obsessional and compulsive behaviors experienced by an individual. Before the MOCI, such assessment relied heavily on subjective clinical interviews; this instrument allowed for a more quantifiable method.

Beyond initial descriptive assessment, the MOCI is widely used as an outcome measure. It allows clinicians and researchers to track changes in symptom severity reliably across time, making it an invaluable tool for evaluating the efficacy of specific treatments, including cognitive-behavioral therapy and pharmacological interventions. Furthermore, the subscale scores enable researchers to categorize patients based on their dominant symptom profile, such as those driven by contamination fears (washing/cleaning) versus those driven by uncertainty (excessive checking).

Construct

The MOCI operationalizes the psychological construct of obsessional-compulsive symptomatology. This construct is defined by the presence of disruptive and distressing obsessions (unwanted, recurrent thoughts or images) and compulsions (repetitive behaviors or mental acts performed to reduce anxiety or prevent a dreaded event). The scale is a classic example of a self-report measure designed to map the external manifestations of this internal disorder.

Factor analytic studies conducted during the scale’s development identified a robust four-factor structure that underpins the scoring: Checking, Washing/Cleaning, Slowness, and Doubting. These dimensions are considered representative of the core phenomenological expressions of Obsessive-Compulsive Disorder (OCD) prevalent in clinical populations. The total score provides an overall index of severity, while the subscale scores offer a detailed profile of the individual’s dominant compulsive type.

Validity

The Maudsley Obsessive-Compulsive Inventory has consistently demonstrated strong psychometric properties, particularly concerning its validity. Early validation efforts, highlighted in the original 1977 publication, established robust criterion validity by successfully differentiating individuals diagnosed with OCD from both non-clinical control groups and other psychiatric populations, thereby confirming its diagnostic utility.

Concurrent validity is supported by evidence showing statistically significant correlations between MOCI scores and scores obtained from other established scales measuring anxiety, distress, and obsessive-compulsive traits. Its capacity to detect meaningful reductions in symptom scores following effective treatment further underscores its sensitivity and clinical value in monitoring changes in obsessional-compulsive complaints over time.

Reliability

The MOCI is generally regarded as a reliable measure, particularly when considering the total score. Internal consistency, a measure of how well the items correlate with one another, is typically high, with Cronbach’s alpha coefficients commonly reported in the 0.80 range or higher in samples of clinical patients. This suggests the scale effectively measures a unified underlying construct.

Furthermore, the scale exhibits good test-retest reliability over short intervals, indicating that the scores are stable, provided the patient’s clinical status has not changed significantly. It is important to note, however, that reliability indices for the individual, shorter subscales (e.g., Slowness or Doubting) may sometimes be lower than the total score, a common limitation of brief factor-derived subscales. Despite this, the MOCI remains a stable and reliable instrument for initial screening and tracking the major dimensions of obsessional-compulsive complaints.

Factor Analysis

The development and subsequent validation of the MOCI were heavily dependent on factor analysis, which established its multidimensional structure. Although minor variations in factor structure have been observed across diverse samples, the original research consistently identified and supported four primary factors that form the basis of the standard subscales:

• Checking Compulsions: This factor includes items related to repetitive behaviors performed to prevent anticipated harm or to ensure correctness, such as repeatedly checking household appliances, doors, or written work.
• Washing/Cleaning Compulsions: Items loading highly on this factor reflect fears of contamination, germs, or disease, often leading to excessive cleaning rituals, hand washing, or avoidance behaviors.
• Slowness: This dimension captures the prolonged time taken to complete simple, routine tasks due typically to extreme meticulousness, perfectionism, or the need to repeat actions until they feel “just right.”
• Doubting: Items associated with doubting reflect persistent feelings of uncertainty regarding actions already completed, a difficulty in accepting that an act is finished, or persistent indecisiveness.

Instrument

Test Type: Self-report psychological scale.

Format: 30 dichotomous (True/False) items. Scoring involves calculating a total score by summing the number of positively endorsed items (i.e., those reflecting obsessional or compulsive tendencies), and deriving separate scores for the four primary subscales.

Language Available: Primarily English, with extensive global use resulting in numerous validated translations across various languages.

Population Group: Clinical and non-clinical populations.

Age Group: Typically utilized with adolescents (aged 16 and above) and adults.

Population Details: The scale was originally standardized and validated on adult patients receiving treatment for obsessional-compulsive complaints at the renowned Maudsley Hospital in London.

Test Methodology: Administration is typically conducted via pencil-and-paper or digital format. Respondents answer 30 statements by marking True or False based on whether the statement accurately describes their current experience or behavior.

Keywords

Maudsley Hospital, Clinical Psychology, Psychometrics, Behavioral Therapy, Self-report, Compulsions, Obsessions, Psychological Assessment, Outcome Measure, Criterion Validity.

Authors

Author ORCID Identifier: Not specified in source content (N/A).

Affiliation Email addresses: Not specified in source content (N/A).

Correspondence Address: Not specified in source content (N/A).

Permissions & Fee and Test Year

The Maudsley Obsessive-Compulsive Inventory was first published in 1977. Due to its foundational status and widespread academic use, the MOCI is frequently utilized freely by researchers for non-commercial purposes. However, formal licensing or permission may be necessary depending on the specific application, particularly for commercial use or integration into digital platforms.

The original PDF describing a study utilizing the MOCI is available here: http://ses.library.usyd.edu.au/bitstream/2123/4026/1/j-swinbourne-thesis.pdf.

Reference’s

• Hodgson, R. J., & Rachman, S. (1977). Obsessional-compulsive complaints. Behaviour Research and Therapy, 15(5), 389-395. The authoritative source for this scale can be found here: http://www.sciencedirect.com/science/article/pii/0005796777900420.
• Swinbourne, J. (Thesis reference utilizing MOCI). http://ses.library.usyd.edu.au/bitstream/2123/4026/1/j-swinbourne-thesis.pdf.

Items of the Maudsley Obsessive-Compulsive Inventory (MOCI)

IMPORTANT: The following scale items must be preserved in their original language and must not be changed in any way.

Instructions: Please answer each question by putting a circle around the “True” or the “False” following the question.

1. I avoid using public telephone because of possible contamination True False
2. I frequently get nasty thoughts and have difficulty getting rid of them True False
3. I am more concerned than most people about honesty True False
4. I am often late because I can’t seem to get through everything on time True False
5. I don’t worry unduly about contamination if I touch an animal True False
6. I frequently have to check things (eg. gas or water taps‚ doors etc) several times True False
7. I have a very strict conscience True False
8. I find that almost every day I am upset by unpleasant thoughts that come into my mind against my will True False
9. I do not worry unduly if I accidentally bump into somebody True False
10. I usually have serious doubts about the simple everyday things I do True False
11. Neither of my parent was very strict during my childhood True False
12. I tend to get behind in my work because I repeat things over and over again True False
13. I use an average amount of soap True False
14. Some numbers are extremely unlucky True False
15. I do not check letters over and over again before posting them True False
16. I do not take a long time to dress in the morning True False
17. I am not excessively concerned about cleanliness True False
18. One of my major problems is that I pay too much attention to detail True False
19. I can use well-kept toilets without any hesitation True False
20. My major problem is repeated checking True False
21. I am not unduly concerned about germs and diseases True False
22. I do not tend to check things more than once True False
23. I do not stick to a very strict routine when doing ordinary things True False
24. My hands do not feel dirty after touching money True False
25. I do not usually count when doing a routine task True False
26. I take a rather long time to complete my washing in the morning True False
27. I do not use a great deal of antiseptics True False
28. I spend a lot of time every day checking things over and over again True False
29. Hanging and folding my clothes at night does not take a long time True False
30. Even when I do something very carefully I often feel that it is not right True False