Explicitación conceptual y judicativa de concausalidades

Surveys or questionnaires can be effective tools in gathering data about abstract ideas, concepts and beliefs (Artino et al., 2014). They support the collection of data in relation to behaviours that are not directly observable as long as respondents are willing to engage.

Since the construct of perceived SE is domain specific, no all-purpose measure can exist (Bandura, 1997, Bandura, 2006). Non-observable constructs can be difficult to measure using single items, thus a scale can allow for more accurate measurement (DeVellis, 2012).

It is suggested that there can be good reasons to use or to adapt pre-existing questionnaires in seeking to investigate a construct (Artino et al., 2014), often for reasons of ease and practicality. Having assessed a wide range of pre-existing SE instruments and taken into account the demands of

2012), the researcher made an informed decision to amend a pre-existing scale. Therefore, the themes provided by the focus group data were used to adapt a questionnaire to measure TA SE for supporting children with ASD in mainstream primary classrooms. The ASSET (Autism SE Scale for

Teachers) was used as the basis for the electronic questionnaire devised for the study on the basis of the evaluations of its dimensionality, internal

consistency, and construct validity by Ruble et al. (2013). Its domain specificity (i.e., for teachers of children with autism) meant that it most

accurately lent itself to amendment to reflect the task of the TA in supporting children with ASD.

3.7.2.1.1. Devising items

In order to adapt the ASSET, the themes identified from the focus group data were used to devise items to measure TA SE for supporting children with ASD. The items reflected the constructs identified by TAs, and where possible, vocabulary gained via the focus group activity was adopted. In addition to the focus group data, reference was made to findings from the literature review, and to documents including the Schools Autism

Competency Framework (Wittemeyer, English, Jones, Lyn-Cook, et al., 2015) and Education Endowment Foundation guidance on effective use of TAs in schools (Sharples, Webster & Blatchford, 2015) in order to optimise the chances of the tool being representative in terms of TA tasks in relation to children with ASD, and the construct of SE (Appendix O: Item

development for the TASCA, p, 270).

The goal of a scale or questionnaire is to offer a set of items that

respondents interpret in the same way, with accuracy and with a willingness to answer (Artino et al. 2014). In addition to reference to the ASSET items, the Hayes (2000) and Artino et al. (2014) best practice guidelines for writing items was consulted. The researcher sought to avoid the pitfalls identified in relation to research design, including avoidance of double-barrelled items

statements instead of questions (Dillman, Phelps, Tortora, Swift et al., 2009). Items should be phrased in terms of “can do rather than will do” (Bandura, 2006, p.308).

Measuring SE requires “more than simply asking about one’s generalised perceptions of competence in the given domain” (Bong, 2006, p. 290). Asking whether someone is good at certain tasks or possesses certain abilities differs from “asking whether one can execute, with those recognised capabilities, the requisite course of action to meet a variety of situational demands for achieving successful performance” (p. 290).

Bandura (2006) recommends that perceived SE should be measured against levels of task demand. These represent impediments to successful

performance, thus appraisals of perceived SE reflect the level of difficulty an individual feels he/she can surmount. When there are no obstacles to

successful performance an individual is highly efficacious.

Thus constructing a scale requires the identification of the challenges to efficacious performance within the specific domain. The identified challenges are then built into the scale’s efficacy items. Ceiling effects should be

avoided by building in sufficient gradations of difficulty or challenge (Bandura, 2006).

Because SE is concerned with an individual’s perceived capabilities and not with their beliefs about whether they can perform the task at a higher or lower level than another individual, items that ask the respondent to compare their abilities with those of others are not reflective of SE and were not

utilised (Bong, 2006).

3.7.2.1.2. Differentiating responses

Since a pre-existing scale (ASSET) was adapted for this study, a continuous 0-100 scale, as utilised in the ASSET, was maintained (Ruble et al., 2013). As with the ASSET, verbal labels were utilised for the initial and final

response option in an attempt to reduce cognitive effort and reduce

measurement error (Christian, Parsons & Dillman, 2009) with the descriptors “I cannot do at all” and “I am certain I can do” being utilised.

Whilst reverse item scaling has been recommended in order to focus attention upon the direction of scales (Carifo & Perla, 2007), this was not utilised in this study in order to maintain the format of the ASSET scale.

3.7.2.1.3. Number of items

In designing a questionnaire, the number of items required to assess the construct depends upon a range of factors including the complexity of the construct and the level of depth of analysis (Artino et al., 2014). DeVellis (2012) contends that “adequate measures are a necessary condition for valid research” (p. 15), so that conclusions reached are valid. Sarantakos (2012) asserts that a questionnaire should contain as many questions as necessary and as few as possible, with each question having a clear role and purpose (McGuirk & O’Neill, 2005). A questionnaire that is too brief to be reliable is not helpful (DeVellis, 2012) and might represent a poor use of participant time and effort, having ethical implications as well as the scientific ones (DeVellis, 2012).

This advice was taken into account in hand with the expert panel feedback. (Appendix P: Expert panel task prompts for content validation, p. 273). The resulting questionnaire comprised 36 scaled items. Demographic data for participants was gained via a final section of the questionnaire,

comprising 7 closed questions. These were followed by a a question asking whether or not the participant would be willing to take part in a short interview with the researcher at a time and place to suit themselves (Appendix R: Teaching Assistants Supporting Children with Autism – TASCA Scale, p. 276).

Development of a valid and reliable questionnaire is essential in order to reduce measurement error. Once the draft survey was created, content validity was established to ensure that the items contained within the

questionnaire were relevant to the construct of SE of TAs supporting children with ASD in mainstream primary classrooms (Polit & Beck 2006), and to ensure that no key indicators had been omitted (Waltz 2005). In order to achieve this, ASD specialists (members of the local Specialist Teaching Team for language and communication) were asked to trial the questionnaire (Oppenheim, 1992), and comment upon the degree to which items appeared to measure the construct, comprehensibility and clarity of each item, and consider any questions which were ambiguous, leading or biased

(Dreachslin, 1998, Radhakrishna, 2007). Length of time taken to complete the questionnaire was also assessed. (Appendix P: Expert panel task prompts for content validation, p. 273). Based upon the 4 feedback forms received, the final number and content of scale items was determined

(Gehlbach & Brinkworth, 2011) (Appendix Q: Feedback from expert panel task prompts for content validation, p. 274).

3.7.2.1.5. Minimising response bias

Safeguards to minimize motivational effects of self-assessment were built into the instructions and mode of administration of the questionnaire (Bandura, 2006): social evaluative concerns were reduced by asking for completion of the scale without personal identifiers. Additionally, respondents were informed that responses would remain confidential and be used only with codes by the researcher.

The questionnaire was labelled with a general title - Teaching Assistants Supporting Children with Autism (TASCA) - so that there was no pre- judgement of content by respondents (Bandura, 2006) (Appendix R: Teaching Assistants Supporting Children with Autism (TASCA) Scale, p. 276).