Triangulation refers to the use of a combination of methodologies in the study of the same phenomenon. In the military, triangulation means a strategy that uses multiple references to locate the exact position of an object. In reference to Salkind (2010), there are four types of triangulation (p.1537). First data triangulation uses multiple data sources in an investigation. Secondly, investigator triangulation employs several evaluators in observation and in analyzing participant responses. Thirdly, in theory triangulation, multiple theories are used in conducting research or interpreting data. Lastly, methodological triangulation employs several methods to study a single problem. Qualitative and quantitative methods should not be viewed as rival camps, but as methods that are complementary to each other. Single method designs have been found to have weaknesses and therefore, the desirable use of multiple methods has been highly underscored. Thus this method combines the positions of the realist, constructionist and empiricist to get data and information.
The use of triangulation has many benefits compared to single method research designs. Triangulation allows for various data sources to be obtained that lead to a singular proposition about the phenomenon being investigated. According to Mathison (1988), good research obligates the researcher to use multiple methods, data sources and researchers to enhance the validity of their research findings (p.13). This is done by comparing and cross-checking findings. This means that the final conclusions of the research are validated by the various but harmonized data from various sources.
Triangulation is perceived to be a strategy of improving research or evaluation findings. It is suppose to show that the independent measures agree with it or at least do not contradict it. Triangulation is a strong and valid strategy against bias and dismissal of rival ideas so that the truth about a phenomenon under research is established. The convergence or agreement between two methods enhances our belief that the findings are valid and is deemed to represent reality.
In reference to Salkind (2010), studies that employ triangulation typically yield three outcomes: convergence, inconsistency or contradiction (p.1538). Researchers that are influenced by constructivist philosophy are not primarily interested in the convergence of the data, but expansion the existing knowledge on the problem under investigation. Constructivists belief that inconsistency or contradiction is an opportunity to explore multiple realities that surround the subject under investigation. Quantitative triangulation enables the comparison of the establishment of the degree of compatibility of information obtained from different methods. In addition, every type of data has its own strengths and weaknesses and in using multiple methods, the weakness of one method will compensated by the strength of another approach that is concurrently used.
According to Salkind (2010), archived data or information may be limited in could be limited by the specificity of the information written in it, biases of the writer or distortion of information (p.1539). In view of these limitations, the researcher may opt to employ triangulation to minimize these limitations and other possible errors. In summation, combining multiple observers, theories, methods and empirical materials, the challenges of weakness or bias that result from single method design, single observer and single theory studies can be overcome. According to Goodwin and Laura (1996), there is no inherent incompatibility between qualitative and quantitative to the generation of knowledge, and therefore should be both used to realize accuracy and validity (p.157).