As a result, surveys, experiments, and statistical methods anchored in quantitative approaches were favored and considered more rigorous than qualitative designs (JOHANSSON, 2003).
The dominance of research using experimental designs continued through the 1960s and 1970s with quantitative empirical results considered to be gold standard evidence.
 In this article, we examine each of these issues in turn, with the aim of improving our understanding of case study research and clarifying the requisite tenets to consider when designing a case study.
We begin with an overview of the history and evolution of case study research, followed by a discussion of the methodological and philosophical variations found within case study designs.
While still qualitative and inductive, it was deterministic in nature with an emphasis on cause and effect, testing theories, and an apprehension of the truth (BROWN, 2008; YIN, 2014).
 A second generation of case study researchers emerged with the advent of grounded theory methodology (GLASER & STRAUSS, 1967).
Grounded theory "merged qualitative field study methods from the Chicago School of Sociology with quantitative methods of data analysis" (JOHANSSON, 2003, p.8), resulting in an inductive methodology that used detailed systematic procedures to analyze data.
For the researcher new to using case study, such variety can create a confusing platform for its application. Introduction Case study research has grown in reputation as an effective methodology to investigate and understand complex issues in real world settings.
In this article, we explore the evolution of case study research, discuss methodological variations, and summarize key elements with the aim of providing guidance on the available options for researchers wanting to use case study in their work. Foundational Concepts 3.1 Definitions and descriptions 3.2 Methodology or method 3.3 Philosophical orientation 3.4 Philosophical variation 3.4.1 YIN: Realist—postpositivist 3.4.2 MERRIAM: Pragmatic constructivist 3.4.3 STAKE: Relativist—constructivist/interpretivist 4. Case study designs have been used across a number of disciplines, particularly the social sciences, education, business, law, and health, to address a wide range of research questions.