There are two primary methods often used to select a sample: probability (or representative sampling) and non-probability (or judgment sampling). The probability sampling methods select from populations that are unknown to the researcher and usually aim to be representative of the population (Saunders et al., 2009a) . These include simple random, systematic, stratified and cluster sampling approaches. The non-probability methods, meanwhile, rely on the personal judgment and knowledge of the researcher rather than on chance to select sample elements. This method includes convenience, review and quota sampling approaches (De Vaus, 2013).
The researcher adopted a non-probability approach rather than probability sampling since the population was widely dispersed and thus probability sampling would be inefficient (De Vaus, 2013). Moreover, as a large sample is required to reflect populations, it would be very difficult to adopt a valid probabilistic approach in the limited time period available.
The purposive convenience approach refers to a method of selecting respondents who are in the right place and at the right time (De Vaus, 2013). Although there might be some limitations in terms of being highly representative of the population, this method is more advantageous in terms of being more time efficient and less expensive. A purposive convenience strategy is therefore the most appropriate for this study.
De Vaus (2013) suggested that the selection of survey methods should depend on five criteria: response rates, obtaining representative samples, the survey method’s effects on questionnaire design, the quality of the answers and the process of implementing the survey. According to the purpose of the quantitative method in this study, a high response rate and high representative samples were important in data gathering. Although a personal interview has a high response rate and accuracy, the purpose of this section considering consumers is to describe and to understand tourist shoppers. In order to collect the numbers required, interviews were not be appropriate because they are time consuming.
Self-administered questionnaires were, therefore, the best way to collect the data for the quantitative study.
5.5.1 Sampling selection
The population comprised shoppers who cross the border from Laos to Thailand for shopping or for a short period of time for leisure, business and other purposes unrelated to being employed. These criteria meet the World Tourism Organisation’s (1994) definition of a tourist. That is (1) that the purpose of the visit is not for immigration and remunerated employment; (2) the distance of travel should take place outside the normal place of residence; (3) the length of stay should be temporary.
Potential respondents were selected by observing vehicles with Lao license plates and the appearance of respondents. Individuals were asked their, age, place of residence and the purpose of their visit. If they came from Laos and the purpose of their visit was not for working, then they would be asked to participate in the study. One adult (aged over 18 years old) from any group was permitted to take part in the study.
5.5.2 Sample size
A sample size of 450 was chosen due to several considerations. First, the desire to reduce the sampling error as the sample size increases. Hill (1998) believed that a sample of approximately 500 people could provide satisfactory results and reliable information.
Second, according to a quantitative approach, a large sample size is required in order to be able to make valid estimates of the population in each segment. Lastly, with a view to allowing an adequate examination of the multivariate techniques, such as chi-square, the number should not fall below 300 respondents (Hair et al., 2010).
5.5.3 Data collection
Given that a high response rate was required due to cost and time constraints, a self-completion questionnaire was considered to be the best method in this research. The samples were collected from three cities that share a border with Laos (see map in figure 5-3). The choice of these three locations was based on a number of considerations. First, these three cities have high rates of investment and attract a significant number of cross-border tourists. Also, since there are inbound shoppers in the towns, it was possible to find a variety of suitable respondents with different motivations for visiting. Furthermore, since the researcher is familiar with these particular locations, it was easy to manage access and
Figure 5- 3 Data collection locations
The data were collected from several places in these three provinces for four weeks during December 2013 and January 2014. Five college students in each province (fifteen in total) were recruited as research assistants due to their familiarity with the locations and time constraints. Before collecting data, the research assistants were briefed for about 15-20 minutes about the research objectives and how to collect data and target respondents. Data were collected on several different days of a month, including weekends, and in various periods of the day to increase the likelihood of a more diverse group of respondents. In addition, the research assistants were discreetly dispersed in different locations close to
shopping areas, tourist destinations, gas stations, bus stations and international border checkpoints. Those locations were selected due to their reputation as trading areas or as tourist attractions. Furthermore, access and convenience also affected the choice of locations. Each research participant was limited to surveying ten persons/location on each day so as to ensure that the research would encounter respondents who exhibited a variety of different shopping behaviours. The data collection locations are demonstrated in Table 5-8.
Table 5 - 8 Data collection locations
Places to collect data Number of data collections
Date
Nong Khai Province 150 December 2013 – January 2014
Tourist destinations 25
Gas stations 10
Bus terminals 10
International border checkpoints 20
Markets/retail outlets 75
Mukdahan Province 150 December 2013 – January 2014
Tourist destinations/Events 40
Gas stations 20
Bus terminals 0
International border checkpoints 0
Markets/retail outlets 90
Nakorn Phanom Province 150 December 2013 – January 2014
Tourist destinations/Events 25
5.6.1 Development of a cross-border shopper taxonomy
Clustering techniques are appropriate for finding a cross-border shopper taxonomy since these are commonly used in market segmentation. The clustering of members into homogeneous groups was based upon their similarities according to several variables. In addition, cluster analysis helps to determine the homogeneity within clusters and the heterogeneity between groups without making any presumptions for categorising respondents.
A hierarchical cluster analysis approach using the Ward method with squared Euclidean