Selection of the Sample

In any research undertaking, one cannot study everyone everywhere doing everything (Miles & Huberman 1984). In survey research, it is not always essential for the researcher to contact every person in the population of his/her study domain and this is where sampling methods come in (Easterby-Smith et al. 2008). In a broad sense, a sample is defined as the set of elements from which data are collected (Thietart, 2001). The validity of a study can be linked to some aspects of the sample such as the nature of the elements it is composed of, the method used in selecting the elements, and the sample size or the number of elements chosen (Royer & Zarlowski, 2001). In any study, the best situation would be to select a representative sample which draws respondents or individuals from the population in such a way that the sample represents the population being studied. If such a sample can be achieved, then the results of a study can be generalised to the overall population.

The populations identified for this study are comprised of two Libyan groups: external auditors and auditors from the IFA.

External auditors are members of the Libyan Accountants and Auditors Association

(LAAA) who are legally allowed to practise accounting and auditing. Currently, 1500 members of the LAAA are listed as external auditors, but LAAA officials informed the researcher that only about 1000 external auditors were actually practising at the time of the study. The rest of the 500 external auditors were listed but not practising due to factors such as retirement, death, end of practice, migration etc.

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Auditors from the Institute of Financial Auditing are members of the Institute of Financial Auditing (IFA) employed by the government to audit the financial statements of its corporations. Because of the large amount of work before the end of every financial year, the IFA also contracts external auditors to audit some financial statements of state-owned companies. According to the registers of the IFA, the number of auditors working for the IFA is around 400.

The main purpose of including respondents from EA and IFA is to explore whether the explanatory variables are differentially related to the two subsamples and also to ensure that the sample of this study is representative of the entire auditing sector in Libya and both private and public companies. There is no evidence or existing research to suggest that perceptions between vary EA and IFA members in Libya and this present study also does not advance a hypothesis anticipating any such difference. Nevertheless, choosing respondents on the basis of their EA and IFA affiliation is a good measure to ensure the representativeness of the whole target population. It will also allow the study to explore if there are any discernible differences in perceptions between EA and IFA.

Sekaran (2003) argues that there are two major kinds of sampling designs: probability sampling where every element in the population has an equal chance of being selected as a subject, and non-probability sampling where elements are predetermined for selection. In this method of sampling, non-replacement sampling is used in order to avoid the possibility of choosing a particular element more than once. According to Sekaran (2003), the rationale for using this kind of technique is:

a) To offer the most generalisability or the most representative sample; and b) To minimise bias and enable the estimates of sampling errors to be made.

For the purposes of this study, probability sampling was employed to select subjects from the targeted groups. Because most of the economic, financial and commercial activities in Libya are conducted and performed in major cities such as Tripoli (the capital city of Libya), Benghazi, Ez-Zawia and Misurata, the sampling process of selecting subjects from the two targeted groups was confined to these main cities. It was observed that:

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• Most economic and business activities are carried out in these cities; and

• The headquarters and their main branches of the commercial and state banks, the Institute of Financial Auditing and the Taxation Board are located in these cities. Saunders et al. (2009) have argued that a sample size of 30 or more will usually result in a sampling distribution for the mean that is very close to a normal distribution. In addition, they argue that samples of larger absolute size are more likely to be representative of the target population than smaller samples and the mean for the sample is more likely to equal the mean for the population. In contrast, Cohen & Manion (1980) believe that there is no exact number or percentage that can be universally prescribed as the ideal sample size for all studies. However, it has been suggested by some authors that there are a few general considerations that need to be kept in mind when deciding the size of the selected sample. These include the kind of statistical analysis that is planned, the expected variability within the samples and the results, the size of the entire population, the traditions in the particular research area regarding appropriate sample size, and the time and cost of conducting the research (Collis et al. 2003; Remenyi et al. 1998a; Saunders et al., 2009; Sekaran, 2003). After considering all of the above points, the sample sizes of each targeted population in the current study were decided as follows: 300 subjects from the EA group and 150 subjects from the IFA group.