RESEARCH METHODOLOGY
3.4 SAMPLE AND SAMPLING PROCEDURE
3.4.1 Sample
The following were the study sample forprimary data:
• Health workers
These were nurses,policy makers at ministry of health,directors and nurse managers at provincial and district levels of the public health care system.
• Nurses seeking verification of their qualifications for purposes of registering and working outside the country
• Nurse migrants visiting Zambia at the time of data collection The following were the study sample forsecondarydata:
• Nurses whose names were on the GNC records as having verification of their qualifications sent outside the country in the last 10 years; January 1995 December 2005.
For quantitative data, the study sample was obtained through multi stage sampling in order to narrow down the nine provinces to two, the districts in the two provinces to four and the health facilities to four with one per district, until the level where there were clusters of nurses was reached (see figure 1). At this level, samples per each stratum were 50% nurses and 50% nurse educators. Polit and Beck (2004:300) argue that there are no simple formulas that can indicate how large a sample is needed in a quantitative study.
The two maintain that the larger the sample,the more representative of the population it is likely to be, and that smaller samples tend to produce less accurate estimates than larger ones; thus the larger the sample, the smaller the sampling error.
For the qualitative data, there were 33 participants in the four focus groups discussions;
one per district with eight in the first, nine in the second, ten in the third and six in the fourth groups respectively. The key informants interviewed comprised one policy maker at national and 4 directors at district levels (I per district).
3.4.2Sampling Procedure
Williams (2003) refers to sampling as a more formal process of selection and a search for typicality; and further refers to selection as implying the most suitable choice, for whatever purpose.
Quantitative data
A multistage sampling approach was adopted for this study. According to Bless and Higson-Smith, (1995), the principle underlying multi-stage sampling is to start by sampling a population which is much more general than the final one. These authors explain that in the second stage, on the basis of the first sample, a new population is considered, one that is less general than the first one, and a new sample is subsequently determined, The procedure is continued until the population to be investigated is reached and a final sample is drawn. At each stage, sampling is done in a random way (p.93). In this study,the approach that was used first selected the provinces, then the districts from the selected provinces, followed by the health facilities in the districts that participated in the study.
The first stage in the multistage sampling in this study involved random sampling of 2 provinces from the country's total of 9. In the second stage, 2 districts were randomly sampled from each of the 2 provinces. The total number of participating districts was thus 4. In the third stage, a total of four health facilities were purposively selected, thus one health facility per district. The multistage sampling approach was used only up to the health facility level where there were clusters of nurses within the health care facilities. At this stage, stratified samplingmethod was used to select study participants (Figure I).
According to Bless & Higson-Smith (1995), the principle of stratified random sampling is to divide a population into different groups called strata, so that each element of the population belongs to one, and only one stratum. Then, within each stratum, random
sampling is performed using either the simple or the interval sampling method. According to these researchers, simple random sampling, or even systematic random sampling in its purest form is seldom used in social sciences research because it is cumbersome for large populations,but it becomes a useful tool when used as part of other random sampling techniques, such as stratified sampling methods.
In this study, each of the populations of nurses in the four districts that were selected was divided into three strata of registered nurses, enrolled nurses and nurse educators.Nurse educators comprised tutors or lecturers and clinical teachers working as school staff and nurses attached to schools to assist either with classroom or clinical teaching on part time basis. This method was used in order to enhance representation of the nurses in the study.
A list of nurses at each respective health facility and school saved as a sampling frame.
There were three lists; one for registered nurses, the second for enrolled nurses and the third for nurse educators. Within each stratum, a random sampling method was used to select participants for the study (Bless & Higson-Smith, 1995).
Figure 3.1: Summary of the Sampling Strategy for Quantitative data: Multistage Sampling Method
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HlFacility - Health Facility RNs - Registered Nurses ENs - Enrolled Nurses
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Records of nurses with verification of their qualifications sent to other countries during 1995-2005 were stratified into two strata of registered and enrolled nurses. Systematic random sampling was used to select records of nurses whose verification of their qualification were sent outside the country in the last 10 years from each stratum of nurses. These records were kept by the General Nursing Council of Zambia (GNC), the professional regulatory organization for nurses responsible for the setting of standards in nursing education and practice and for the registration of nurses trained both outside and within the country. The GNC full mandate is embodied in the Nurses and Midwives Act No 31 of 1997. One of its roles in maintaining standards for nurses wishing to register with other nursing councils or regulatory institutions is to verify the qualifications of individual nurses upon request,through written statements or completion of verification forms (Nurses& Midwives Act, 1997).Apart from registers for nurses, according to this Act, the GNC is expected to maintain a record of its transactions among which are records on verifications which are sent to respective nursing councils or countries. Nurses normally apply for such verifications and pay a fee to support the processing and postage of the verification statements.
Qualitative data
Purposive samplingwas used to select between six to ten informants per each of the four respective focus group discussions
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per district) that were conducted in the four selected districts.Purposive sampling method was used to select a total of five directors, one per each of the four districts, and one at national level for focused interviews, because, according to experience, individuals at provincial and district director's level were responsible for the
management of their respective districts and provinces respectively and had experience with issues associated with recruitment and deployment of nurses in their areas. The same applied to the director's national level role of policy and deployment of nurses.
According to Silverman (2002), purposive sampling allows the researcher to choose a case because it illustrates some feature or process in which the researcher is interested.
Silverman (2002) also argues that provided the researcher has thought through the options, it is unlikely that the selection will be criticized, and states that sampling in qualitative research is neither statistical nor purely personal, but that it is, or should be theoretically grounded. The purposively selected sample of participants provided data on nurse migration and its perceived impact, a phenomenon that was grounded in the conceptual framework developed and adapted for this study.
Snowball method was used for sampling of 13 nurses who had migrated to other countries and were in Zambia at the time of data collection. Each of these was asked to identify others who had worked outside the country and were in Zambia at the time.
These nurses were interviewed until data saturation was reached. According to Fink (1995), snowball sampling is a method where previously identified members identify other members of the population. The method is used in a situation where it is not practical to obtain a list of members of a population. In this study, it was not possible to obtain a list of the nurses who had migrated and had come to Zambia for visiting or other reasons.
3.4.3Quantitative Data Multistage sampling
The following were the stages followed in multistage cluster sampling of clinical nurses and nurse educators who participated in the study:
Stage 1: Two provinces were randomly selected from a total of nine.
Stage 2:Two districts per each selected province were randomly selected to obtain a total of 4 districts
Stage 3: One health facility per each selected district was purposively selected for the
study (a total of 4 health facilities).
Stage 4: Nurses in each of the four selected health facilitieswere stratified into three strata of nurses. The first stratum comprised registered nurses,the second enrolled nurses and the third nurse educators comprising lecturers or tutors and clinical teachers.
Systematic random sampling
Systematic random sampling was used to select nurses and nurse educators who participated in the study.
Records on all nurses issued with verification of their qualifications in the last ten years (from General Nursing Council of Zambia) were stratified into two strata of registered and enrolled nurses respectively. Systematic random sampling was used to select 50% of records for enrolled and 50% for registered nurses for the study.
3.4.4 Qualitative data
• Snowball Sampling- 13 Nurses who had earlier left the country were identified at time of data collection.
• Purposive sampling- Nurses seeking verification of their qualifications between January and December,2006.
• Purposive sampling- participants for each of the four focus groups
• Purposive Sampling- five directors: one provincial,three district, one director at national level
3.5 DATA COLLECTION PROCESS AND INSTRUMENTS