A novel elastin gene mutation results in an autosomal dominant form of cutis laxa
SUBJECTS AND METHODS Clinical summary
1. LA SÍNDROME DE WILLIAMS-BEUREN
According to Brink (2007) reliability is concerned with establishing the degree to which a particular measurement is free of random or unstable error. Reliability in this study is measured using the internal consistency method by finding Cronbach’s alpha (Sekaran, 2003; Cooper & Schindler, 2001). There are a number of devices for checking reliability in scales and tests, such as test-retest; which is the administration of the same test a period of time after the first. In this study, due to the time shortage and administrative limitations of firms, the test re-test method could not be performed to assess reliability, thus internal consistency was assessed using Cronbach’s alpha, which can be written as a function of the number of test variables and the average inter-correlation between the variables (Abdulla, 2010). The formula for the standardized Cronbach‘s alpha can be shown as:
Where N is equal to the number of variables, c-bar is the average inter-item covariance among the variables, and v-bar equals the average variance (Ahmed, 2010). In order to find internal consistency reliability, an item analysis is performed on each item and a Cronbach’s alpha designed (Miller 1995). According to Akhtar (2009), cited in Nunnally (1967), values of alpha ranging from á = 0.50 to 0.60 are regarded as satisfactory for descriptive studies. Cronbach’s values for all other constructs are relatively high. Hereafter, the values of Cronbach’s alpha in this study indicate that the scales used in the instrument are adequate and suitable. When collecting questionnaires, attempts were made to ascertain that it was the respondents who had completed them by having an informal conversation where possible. The way in which the questionnaire was distributed facilitated the avoidance of errors resulting from ambiguity. The more consistently the subject responds, the greater the variability between the subjects in the sample and the higher the Cronbach’s alpha value will be. The widely accepted cut-off in the social sciences is an alpha value of 70 or higher, which 1 3 4
will give a standard error of the measurement of over half; meaning a standard deviation of 0.55 (Allen, 2002; Brink, 2007).
3.10.2 Validity
Validity is the extent to which research findings accurately represent what is really happening in a given situation (Hussey & Hussey, 1997). That is, when we develop an instrument for tapping into a concept, how can we be reasonably sure that we are measuring the concept we set out to and not something else (Sekaran, 2003). Validity refers to the extent to which a test measures what we actually wish to measure. Validity is undermined by research errors, such as faulty research procedures, poor samples, inaccurate or misleading measurements and ambiguity about causal direction (Hussey & Hussey, 1997; Saunders et al., 2003). Therefore, to meet the criteria for validity, the researcher should develop an accurate measurement tool that better reflects understanding of the questions included in the measurement tool; this guarantees that all respondents are enlightened to respond to all questions. In other words, the instrument of measurement should be understandable by all respondents to be certain that findings are really about what they appear to be about. In this study, to ensure high validity and to increase the validity of the two data collection methods, the following procedures were undertaken.
To ensure external validity, the entire population was targeted as the sample for this study, with high response rates of 86% and 68% for the questionnaires and semi- structured interviews, respectively.
To meet some of the validity requirements, an extensive literature review was undertaken to define and clarify the scales and measures used in this research. Many items and scales used are adopted from several studies that place an emphasis on meeting the requirements of validity and reliability. In this respect Sekaran (2003) asserted the need to use well-validated and reliable measures to ensure that research is scientific. Sekaran (2003) also high-lighted the importance of making use of measures and scales that are already developed, as their reliability and validity have been established by their developers and they are already reputed to be good. In addition, the items in the questionnaires were scrutinized and pre-tested, using several pilot
testing stages, by many academic and experts and managers to judge the content and face validity of the questionnaires. This suggests that the validity of the content of the questionnaires is established.
This research uses both strategies to test content validity (face validity) by, firstly, asking five experts in the field of construction to provide their judgments on the questionnaire, especially on the items in each set (concept), to check whether individual items correspond with the concept. Some minor revisions were made to the instrument according to their suggestions. Secondly, the instrument was pre-tested twice with a sub-population and a group of PhD students and one pilot study was tested on a group of similar subjects to the population. From this, extensive information and some constructive and encouraging comments on the questionnaire’s design and content that would help in validating the content of the questionnaire were obtained.3.11 Summary
This chapter introduced the methodology applied to meet the research aim and objectives of the study. A clear difference has been made between research methodology and research methods. Drawing on the epistemological, ontological and axiological assumptions, positivism was chosen as the appropriate paradigm. A review of the research methods revealed that survey was the most appropriate approach for eliciting the relevant data. Subsequently the design of the survey instrument was described following which a commentary was also provided on piloting of the questionnaires. This thesis adopts a positivist philosophy and two stages of inquiry. Firstly, the inductive modelling of the pressure/operational response model of TNA in the Iraq construction industry , based on the literature review and basic content scanning of a series of published 'snapshots' of TNA practices in a range of organizations. This inductive model is then tested deductively using opinion research, via the administration of a survey. This chapter describes the research methodology that was adopted and 'triangulates' research strategies as a means for achieving the main aims and specific objectives of the research. The research methodology adopts well established research approaches and is divided into five main sections: literature review, 1 3 6
survey study, model development and implementation of the model, and evaluation of the model with feedback. The next chapter will examine the current training needs assessment within Iraqi construction industry. The work was carried out in the form of a survey, in order to get a real feel for the theoretical material which has been examined in this chapter. This study is using Hypothesis test for data analysis of construction organisations in Iraq. Independent sample t-tests (Sekaran 2003) were used to explore the differences between two groups such as constructions engineers groups. They are used because this study needs to compare the mean score on some continuous variables between the view of the four principal actors in a construction project, i.e., civil Eng , Project Engineers , Architect and site manager for each variables. The null hypotheses are stated below;
Hypothesis 1: There will be no significant difference in the perception of the four principal actors in a construction project, i.e. civil engineers, project engineers, architects and site managers, regarding the importance of TNA in identifying training and non-training needs that should be used for setting training goals and organizational goals respectively. However, these goals should also provide basis for the future TNA.
Hypothesis 2: There will be no significant difference in the perception of the four principal actors in a construction project, i.e. civil engineers, project engineers, architects and site managers, regarding the importance of TNA in providing information on training and non- training needs that should be used for employees’ professional and personal development respectively.
Hypothesis 3: There will be no significant difference in the perception of the four principal actors in a construction project, i.e. civil engineers, project engineers, architects and site managers, regarding the importance of TNA in identifying training and non-training needs that should be used for managing change in the organization.
Hypothesis 4: There will be no significant difference in the perception of the four principal actors in a construction project, i.e. civil engineers, project engineers, architects and site managers, regarding the importance of TNA in identifying training needs that should be used for employees’ career development.
Hypothesis 5: There will be no significant difference in the perception of the four principal actors in a construction project, i.e. civil engineers, project engineers, architects and site managers, regarding TNA in identifying training needs that should be used for improving the trainees’ level of knowledge and skills
Hypothesis 6: There will be no significant difference in the perception of the four principal actors in a construction project, i.e. civil engineers, project engineers, architects and site managers, regarding the importance of TNA in identifying training needs which help manage and increase the level of trainees’ motivation to learn.
Hypothesis 7: There will be no significant difference in the perception of the four principal actors in a construction project, i.e. civil engineers, project leader engineers, architects and site managers, regarding the importance of TNA in identifying training needs and therefore, by administering training only for the identified needs making it cost effective.
Hypothesis 8: There will be no significant difference in the perception of the four principal actors in a construction project, i.e. civil engineers, project engineers, architects and site managers, regarding the achievement of training effectiveness through proper TNA.
1 3 8