Coercive- Composite Abuse Scale (C-CAS)

The Coercive-Composite Abuse Scale (C-CAS) is a self report list of partner behaviours survivors see as abusive and is easily administered. The measure provides standardized subscale scores on four dimensions of coercive control and intimate partner abuse.

The C-CAS consists of 30 items presented in a six-point format requiring respondents to answer “never”, “once”, “a few times”, “monthly”, “weekly” or “daily/almost daily” in a twelve-month period. Psychological Control (13 items), Severe Coercive Control (8 items), Sexual and Reproductive Coercion (6 items), and Technology-Facilitated Threats (3 items).

‍Similar to the original CAS, the C-CAS can be used as a research tool in clinical or community settings for risk factors, prevalence and health associations or as an outcome measure in response to interventions.

‍Adaptations of the original CAS include a ‘Think aloud’ study with survivors that made suggestions for better language and a shorter version of the CAS developed by a Canadian group of researchers. Subsequently, the omission of some types of abuse was described from feedback from survivors.

‍The original CAS has been translated into Vietnamese, Arabic, Dutch, Bengali, Russian, Spanish, Malaysian, Japanese, German. It has been used with men (although has limited validity in this population) and also for child exposure to adult IPV.

• Background

  In the late 90’s, the Composite Abuse Scale was developed to respond to issues in how domestic violence was defined.  Inconsistent definitions of domestic or intimate partner violence in research and practice result in varying information about its prevalence and associations. 30 years later these issues are not resolved.

  The Coercive-Composite Abuse Scale (C-CAS) measures aspects of coercive control, a dominant pattern of domestic or intimate partner abuse against women.
  
  What is coercive control and intimate partner abuse?
  
  Domestic violence mainly refers to violence and abuse between partners.
  Family violence refers to violence and abuse occurring between family members.

  ‍From a health perspective, domestic violence is best understood as a chronic pattern, characterised not by episodes of physical violence that punctuate the issue, but by the emotional and psychological abuse that the person uses to maintain control over a partner. Most survivors report, the physical violence is the least damaging abuse they suffer: it is the relentless psychological abuse that harms and isolates them.

  ‍Coercive control by partners is an ongoing pattern of domination by which partners interweave repeated physical and sexual violence with intimidation, sexual degradation, isolation and control. The primary outcome is a condition of entrapment that can be hostage-like in the harms it inflicts on dignity, liberty, autonomy and personhood as well as to physical and psychological integrity.

  The term “violence” is too limiting, instead “abuse” is preferable because it is inclusive of the actions people use to control their partners.

  Intimate Partner Abuse (IPA) is any behavior within an intimate relationship that causes physical, psychological or sexual harm to those in the relationship, includes: physical aggression, psychological abuse, forced intercourse & other forms of sexual coercion, various controlling behaviors (World Health Organization)

  ‍A comprehensive definition takes into account varying types of abuse (e.g. emotional, physical and sexual), severity and frequency of abuse, and intention of the abuse. This last factor is very hard to measure from a survivor viewpoint.

• Administration and Scoring

  The C-CAS is in self-report format and can be used online, written format or in telephone and face-to face interviews which requires additional selection and training of interviewers.

  ‍The following instructions and testing conditions are recommended to ensure safety of participants:

  1. The introductory information alerts participants that the questionnaire contains questions about emotional
     well being, including domestic violence.

  2. It is best for administration to be conducted in a private setting. If it is sent to people at home it is vital that some checking beforehand has occurred as to whether this is safe or not e.g. during the recruitment and consent procedures.

  3. There should be an opportunity given to respondents to ask clarifying questions either by phoning or speaking to a research assistant.

  4. The research assistant should be trained in a distress protocol.

  5. All participants (regardless of whether abused or not) should be given a resource card to access available services.

  6. Most people can complete the C-CAS in 5 minutes, or in less than 15 minutes with associated questions about socio-demographics and lifetime abuse.

  There are four key steps in the CAS scoring and categorisation process outlined in the publication.
  These include calculation of: 1) item scores; 2) subscale scores; 3) cut-off points; and then categorisation of 4) abuse pattern.

  1/ Item Scores
  
  There are 30 items in the CAS, each of which is scored between 0 and 5, as follows: Never = 0 Once = 1 A few times = 2 Monthly = 3 Weekly = 4 Daily/Almost daily = 5. None of the items are weighted.

  2/ Subscale Scores

  ‍The C-CAS is made up of 4 subscales: Severe Coercive Control (8 items range 0-40), Sexual and Reproductive Coercion (6 items range 0-30), Psychological Control (13 items, range 0-65), and Technology-Facilitated Threats (3 items, range 0-15)

  3/ Cut-off Scores
  
  Once subscale scores have been calculated, these should be compared with a pre-decided cut-off score for each subscale. If a participant’s score is equal to or greater than the cut-off score, they are determined to have experienced that type of abuse.

  ‍
  Recommended Cut-off Score

  Severe Coercive Control: 1

  Sexual and Reproductive Coercion: 1

  Psychological Control: 3

  Technology Facilitated Threats: 2

  These cut-off scores aim to maximise true positives, while minimising false positives. They were developed based on experience in developing the original CAS. Respondents may be classified as not experiencing abuse when in fact they are (false negative). Alternatively, they may be classified as experiencing abuse when in fact they are not (false positive). A perfect screen would have a 0% false negative and a 0% false positive rate. All respondents who have experienced abuse would be classified as abused, giving a 100% true positive rate. While this level of accuracy is rarely achievable, the aim is to use a cut-off score that is as close to this ideal as possible.

  4/ Abuse Pattern Categorisation

  Once cut-off scores have been implemented, the type of abuse experienced by each respondent can be categorized. Using the four subscales above, there are many possible combinations of abuse type that participants may experience. These combinations can be reduced to four major categories of abuse experienced by people.

  In this categorisation process, Severe Coercive Control (SCC) takes precedence over the other forms of abuse, so that any participant who has experienced SCC falls into the SCC category, and usually they have experienced the other forms of abuse (Pattern 1). The second pattern includes all participants who have experienced Sexual and Reproductive Coercion in combination with Psychological Control or Technology Facilitated Threats. Participants who have experienced Psychological Control, but no other forms of abuse, fall into the third pattern, Psychological Control Alone. The final pattern contains all participants who have experienced Technology Facilitated Threats and/ or Psychological Control, but not any other type of abuse.

  Should missing data be substituted?
  If a participant has missed fewer than 30% of items on a subscale, data substitution is likely to be appropriate for that subscale. However if the proportion of items missing is 30% or greater, it is recommended that data substitution not be used. In this case, the full subscale would normally be treated as missing.