La importancia del colegiado y la colaboración.

Field (2009) noted that “validity refer to whether an instrument measures what it was designed to measure”. The design of the questionnaire and semi-structure interview questions depends

on has to be tailored to the perspective of the sample population and size. The nature of validity as stated by Field (2009) can be criterion validity, which depends on the existing phenomenon, or situation or content validity when the design of the research instruments fulfils the requirement for data collection. In this study, the use of pilot study has helped in assessing the validity of research instruments. Also, the design of the questionnaires includes a brief explanation of kaizen and a participant information sheet detailing the required information to fill the questionnaire. Reliability pertains to the acquisition of the best result under different

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conditions (Field, 2009). In addition, Saunders et al. (2015) opined that in other to enhance the validity and reliability of a study mixed method approach is vital. This justifies the choice of mixed method approach for this investigation. Triangulation of data, which involve the mixed method approach, was used for objectives two and three. In order to ensure the validity and reliability of the data collected, planning the research design from the onset is very vital. Four (4) expert interviews were conducted for validating the Kaizen costing framework. This pointed out the errors and omissions. The various types of validity will be explained in detail in relation to this investigation.

3.8.1

Criterion-related validity

According to Drost (2011), criterion-related validity is a form of predictive validity. This is also the degree of the relationship between a test measure and another criterion; this is usually evaluated using correlation. This implies that the outcome of a survey can be compared with other existing records to ensure that it is correct. In this instance, some of the details the cost and project managers provided were corroborated with what the employers provided in the interview sessions. Furthermore, the quantitative data provided by the respondents was an indication of what is existing in the cost management circle in Nigeria. This was corroborated using the existing literature. The comparison, which can occur in the future, is referred to as

predictive validity. Hence, the researcher has collected the data, but the measure to compare this data is not yet available.

Concurrent validity is a type of criterion-related validity where the criterion in the research instrument exists alongside the responses provided. Therefore, the measures provided for each of the criteria are available to compare with the data. Convergent and discriminant validity

is another form of construct validity where the validation process is tested across various measures, and the divergent validity allows the researcher to test the data with other distinct measures which are related at the same time.

3.8.2

Content validity

Content validity is a qualitative way of addressing ambiguity in social science research. Content validity ensures that the questions asked in the questionnaires or interviews are related to the basic knowledge level of the respondents. This also depends on the type of research. This study used terms such as kaizen and kaizen costing. For the purpose of data collection, the

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researcher used the term “continuous improvement in cost management as the basic terminology. Also, certain concepts relating to continuous improvements were asked in the survey questionnaire and interviews. The concepts are stakeholders’ involvement, perception towards change, post-project review, waste reduction policy and use of templates for the easy conduct of post-contract cost control. The basic method of conducting content validity is by asking a number of questions about the questionnaire and the judgement of experts with a high level of experience. This study made use of expert opinions for validation and pilot study for the survey instruments.

3.8.3 Construct validity

Construct validity was obtained via multiple sources of evidence. This began with the literature review of existing books, journals, documents and reports to establish a background to post- contract cost control, kaizen costing in construction and small and medium scale construction industries. Furthermore, interviews with experts and professionals within the SMSCC were embarked to assess their perception towards change and innovation in the area of post-contract cost control. In a bid to construct validity with respect to the peculiar survey strategy encompassing quantitative and qualitative interviews, a similar approach as described above was initiated whereby specific documents and reports peculiar to each case were reviewed, and findings were cross-referenced with interviews.

3.8.4 Face validity

Drost (2011) opined, “Face validity is the subjective judgement on the operationalisation of a construct”. Face validity has been criticised by many authors as not being good enough for

validation because it only depends on the subjective view of the researcher based on personal opinion (Trochim, 2006). This form of validity is under construct validity, but it is rarely used because it is not enough to form of validity for research purposes. Although, subjectivity is required through the research process, it has very little effect on the strength of validation.

3.8.5 Translation validity

Just like face validity, which is based on subjective judgement, translation validity also depends on the subjective opinion of the researcher for operationalisation. Translation validity refers to the extent in which the operationalisation portrays the intent of the construct. The research

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instruments have to be designed to reflect the overall theoretical background of the study. Therefore, the judgement is based on personal experience and opinion.

3.8.6 Internal Validity

The research will follow an explanation-building approach whereby certain conditions will yield to other conditions thus establishing a causal relationship (Yin 2013). The explanation building aspect, in this case, starts with the interview analysis with the contractors and survey questions by the employees. Internal validity demonstrates a causal relationship between two variables, thereby distinguishing it from spurious relationships (Saunders 2015). However, internal validity cannot be applied to exploratory studies (Yin 2013). “Testing” being a threat to internal validity as mentioned by (Saunders 2015) was met with a notification of ambiguity to all participants to negate the effect it might have on the process.

3.8.7 External Validity

Generalising a research’s findings to other relevant settings or groups shows external validity Saunders 2015). Furthermore, establishing a domain whereby the findings of research can be generalised exhibits external validity (Yin 2013). Hence, it is, therefore, necessary to replicate a study in another context(s) to be able to confirm generalizability. External validity related to the generalising to other conditions, duration and respondents. External validity addresses the findings from another point of view that is not usually within the group of participants or stakeholders.

3.9 Research reliability

Reliability relates to the consistency of a measure. It deals with the extent to which the data obtained are affected by random errors. When random errors build up over time, it affects the validity of the data. Hence, errors are unavoidable in data analysis. Nonetheless, there is a level of reliability, which is acceptable for a good data analysis. There are many ways to determine the reliability of data: this is based on the type of reliability. According to Drost (2011) there is four type of reliability, they are inter-rater reliability; test-retest reliability, parallel-forms reliability and internal consistency reliability.

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3.9.1 Inter-rater reliability

Inter-rater or inter-observer reliability is carried out when there is an exploration of opinion, behaviour or perception towards a judgement. Therefore, there is more than one judgement for the same opinion. This implies that different stakeholders provide a various judgement on the rating. The level of agreement of this study can differ. This study used Kendall’s coefficient of concordance to establish the level of agreement from the Likert scale for post-contract cost controlling techniques. The first perception was of the level of effectiveness and the second was from the angle of importance. The results showed consistencies in the rating between the two perceptions. This example of inter-rater reliability enables the researcher to address the loopholes in the study.

3.9.2 Test-Retest Reliability

Test-retest reliability involves finding out if the output of the data from the same set of respondents is the same over a period. Hence, the questionnaires are administered to a set of respondents. This is later re-administered at a different time in the future. This allows the researcher to assess the responses from a different point in times. A correlation test can be conducted on the two sets of data to evaluate the reliability.

3.9.3 Parallel-forms reliability

In parallel reliability the same questionnaires or interview questions are administered to the same population at the same time. Therefore, the researcher will design the questions towards a particular set of the construct. The construct in this study is continuous improvement in construction. This construct was investigated through the same set of the population with various questions in the questionnaire. The construct was divided into sub-constructs, which targeted the knowledge level, and understanding contractors, cost and project managers have in the area of continuous improvement. The study did not distribute separate questionnaires to but the questions posed within the questionnaire were a repetition of the intended construction that is continuous improvement.

3.9.4 Internal consistency reliability

This type of reliability makes use of one single measurement instrument administered to the same population to evaluate reliability. Inter-item correlation within the group of constructs

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provides enough evidence for a good evaluation of the reliability. Another method of conducting internal reliability is through split-half. Split-half reliability randomly divides the items, which supports the concepts into two. Cronbach alpha is an average of all the possible halves. Pallant (2016) stated that Cronbach alpha is displayed the mean inter-item correlation for the construct. The Cronbach alpha test available on SPSS 23 was used for the reliability of the data for this study. The reliability and validity of the research in sections 3.9 and 3.8 respectively, created a research error checking system for the study. Ethical considerations of the study provide a good to ensuring the study ends in an ethical manner.