According to Silverman (2010:275), Mertler (2009:126) and Babbie et al (2003:122), a study is valid if it accurately represents the social phenomena to which it refers to. In
other words, the extent to which an empirical measure reflects the “truth” and focus or the real meaning of the concept under consideration.
4.6.1 Content validity
According to Babbie et al (2003:123) content validity refers to how much a measure covers a range of meanings included within a concept. Prior to developing the data collection instrument, the researcher reviewed a wide range of literature on PTSD and the approaches used to collect data and various models on trauma and PTSD management. Confidential consultations were conducted with specialist psychiatrists and clinical psychologists in and outside of the Mahikeng area. This was done to gather information on PTSD which was specific to the SAPS workers in Mahikeng, which was to be included as content. Furthermore, this was done to request for referrals and to recruit and obtain data on other SAPS workers in Mahikeng diagnosed with PTSD whom the researcher was not familiar with so that they be included in the study. Prior informal surveys conducted with police workers who shared their exposure to extreme types of trauma and consultation made with trauma experts within the SAPS EHW office at national, provincial and local offices gave the researcher an insight into possible content to include in the tool. The researcher’s own experience of the traumatic nature of police work and consultation with workers diagnosed with PTSD enriched the content of the instrument. Furthermore, the researcher ensured that the content of the tool covered the concept of PTSD and a range of closely related aspects such as trauma as well as the inclusion of the SAPS workers’ family members as study participants. In ensuring that all scopes relating to the study topic were covered, the instrument was subjected to a comprehensive examination by experts in the field and the study supervisor.
4.6.2 Construct validity
It refers to the degree to which inferences can legitimately be made from the operationalization of a study to the theoretical construction which that operationalization was based. Construct validity is therefore based on the logical relationships among variables (Trochim 2006:5; Babbie et al 2003:123). In this study construct validity was ensured by not deviating from concepts related to PTSD and making reference to the legislated PTSD diagnosis documents, including the DSM-IV-TR and the Department of
Furthermore, the construction of the data collection instrument was guided by the results arising from consulting a wide range of literature on similar studies as well as engaging various research experts in the field of trauma and PTSD (including the promoters of the study) who ensured that the variables and concepts under study were properly operationalized and not deviated from. The usage of services of a professional language editor and translator ensured construct validity for the study. Existing assessment tools for PTSD and its effects could not be used in this study due to the unique nature of the SAPS organization and the unique traumatic events the workers get exposed to, as compared to that of the general public. The study sought to identify available onsite occupational health and support services provided to the SAPS workers and immediate family members to deal with PTSD in Mahikeng. The existing assessment tools did not provide for this construct to be measured; hence the researcher developed a tool to cover this aspect. Furthermore the inclusion of family members in the study called for the development of a tool that captures specific health and social effects, and for the tool to yield data on recommendations for effective PTSD management by both groups of participants, which would assist in the development of guidelines.
4.6.3 Reliability
Reliability refers to the degree of consistency with which instances are assigned to the same category by different observers or by the same observer on different, repeated occasions (Silverman 2010:275; Babbie et al 2003:119). In this study, reliability was ensured by employing various strategies. Firstly, a relevant study design was carefully chosen, discussed, scrutinized and approved by the study promoters. Furthermore, the sample for this study represented the target population and made inclusion of the SAPS workers’ immediate family members. Prior to the data collection process, all necessary precautions were ensured, such as having health and mental professionals on standby for necessary study participants’ support, given the sensitive nature of the study.
According to Babbie et al (2003:122), another way of obtaining information from people is to utilise measures that have proven their reliability in previous research, thus using established measures. In this study, the data collection tool utilised (In-depth interview questionnaire) was reviewed in literature and has been found to be reliable. The data collection instrument was also subjected to a pre-testing process in order to ensure that it was objective, unbiased and that there was clarity and practice on researched
constructs so as to avoid any ambiguities. With the training and research experience that the researcher had, the researcher conducted in-depth interviews herself and avoided data omissions or incomplete data collection. Replication of collected information was also avoided at all times by the researcher. All participants were requested to be honest in their responses in order to gather objective responses and to minimize subjectivity.