Classification System Sigma Theta Tau International The classification of nursing research is crucial for understanding the vast body of work conducted by nurse researchers. The Nursing Research Classification System (NRCS), developed by Sigma Theta Tau International (STTI), has significantly shaped the way nursing research is categorized and stored. This article provides an overview of the nursing research classification system, its development, and its role in enhancing the organization and retrieval of nursing research knowledge.
Nursing Research Classification System
The first nursing research classification system was developed during the “Survey and Assessment of Areas and Methods of Research in Nursing” project, conducted at Yale University under the direction of sociologist Leo W. Simmons, along with two other sociologists and Virginia Henderson, a renowned nursing theorist (Cowan, MC, 1956). This classification system laid the foundation for cataloging English-language nursing studies in the Nursing Studies Index from 1900 to 1959 (Henderson & Yale University).
The term “study” was broadly defined to encompass any structured effort to solve a problem, including historical and biographical articles, monographs, and analytical (research) articles (Henderson & Yale University, 1959). This classification system categorized nursing research by the fields of interest to nurse researchers.
Issues for Classification
However, this early research classification system was abandoned in favor of a subject heading system that indexed all nursing literature, not just research literature. The subject headings allowed articles to be located based on their content. These headings describe important topics in the field and are usually organized into a tree structure to illustrate the relationships between various topics and subtopics.
While a subject heading system facilitates indexing and retrieval, it does not enable comparisons of studies according to aspects like research design, methods, or other elements of interest in the body of nursing research.
Nursing Research Classification
Despite the shift to subject headings, the idea of a classification system for nursing research persisted. In the early 1980s, Sigma Theta Tau International (STTI), the International Honor Society of Nursing, began developing the Nursing Research Classification System (NRCS). The initial purpose was to categorize fields where nurse researchers conducted studies, identify research subjects and methods, and facilitate the identification and location of nurse researchers.
Now in its third edition, the NRCS includes detailed descriptions of studies, variables, and findings. It serves as the framework for databases combined into what is now known as the electronic “Registry of Nursing Research” (Graves, 1994).
Language and the Structure of Clinical Nursing
The NRCS represents the language and structure of clinical nursing research knowledge and the research knowledge in related domains such as education, administration, management, and more. In this context, “language” refers to the terms used to describe research concepts and variables, while “structure” pertains to the descriptive details of the research, including:
- Demographics: Details about the investigators, dissemination, funding, title, and conceptual framework.
- Methodology and Design: Information on the sample, methods, design, and analysis.
- Relationships: Hierarchical arrangements between the descriptors, accommodating multiple knowledge-generation theories.
STTI Nursing Research Classification System (NRCS)
The STTI NRCS provides a detailed description of the structured inquiry process used in individual nursing research studies. It identifies and logically relates salient characteristics of nursing research studies, focusing on:
- Comparison of Studies: Enables comparisons based on research process details such as design, subjects, and findings.
- Quality Judgment: Allows preliminary assessments of a study’s quality, given its design.
- Direct Indexing: Facilitates direct indexing of the knowledge generated by each study, including variable names and results.
- Comparison Between Studies: Permits comparisons of interest to the nursing profession, such as funding sources and amounts or domains of research (e.g., education, administration, philosophy, culture).
In alignment with the original purpose of locating researchers, the category “Researcher” is the primary hierarchical element.
Short Research Studies
Each researcher may have multiple research studies, with the single study serving as the basic unit of analysis. A study may be part of a larger research project or stand alone. Each research study is classified by:
- Title: The study’s title and focus.
- Conceptual Framework: The theoretical basis for the study.
- Research Domain: The field in which the study was conducted.
- Funding: Information about the study’s financial backing.
- Keywords: Subject headings relevant to the study.
- Dissemination Record: Information on how and where the study was shared.
- Participants/Sample: The demographic details of the study sample.
- Sampling Plan and Scope: Details about how the sample was chosen and the scope of sampling.
- Data Collection Site: The location where data was collected.
- Design Type: The study’s methodological design.
- Extraneous Variables: Factors not accounted for in the study but that could impact results.
- Research Questions: Each study may address multiple research questions.
Research Question Analysis
Each research question in a study may involve multiple analyses. These analyses are classified based on:
- Nature of Inquiry: The theoretical framework guiding the research.
- Procedures: The methods used to conduct the research.
- Data Analysis: Techniques employed to analyze data.
- Research Concepts/Variables: The names of the variables or concepts studied.
- Relationships Studied: If applicable, the relationships between the variables.
- Findings: The study’s results.
Domains of Research Catalog
The NRCS category “Domain of Research” is similar to the first nine categories of the Henderson nursing research classification system. While not identical in detail, these categories are remarkably alike. Henderson’s tenth category, “Conducting Research,” which includes “Research methods and types, including devices and techniques,” forms the primary corpus of the STTI NRCS, while the domains of research remain secondary characteristics.
Storing and Retrieving Research Knowledge
The NRCS provides a framework for a new model of storing and retrieving research knowledge across disciplines. Of all health science disciplines, nursing is unique in having developed a research classification system. This classification system serves as the logical model for the database that organizes the Virginia Henderson Library’s “Registry of Nursing Research.”
The Virginia Henderson International Nursing Library is the only known library that stores research studies according to a research classification system and indexes that research by the names of the variables or research concepts studied.
The NRCS plays an active role in contributing nursing subject headings maintained by the Cumulative Index for Nursing and Allied Health Literature (CINAHL). STTI has permission to use CINAHL’s subject headings in selected NRCS categories, such as funding sources, theoretical frameworks, indexing terms, and data collection sites. This prevents the development of yet another subject heading system to describe the same topics, thereby facilitating searches in both the CINAHL bibliographic database and the STTI Registry of Nursing Research.
As the NRCS gains wider use, new terms employed by researchers will provide data to influence updates to the CINAHL subject heading list. In turn, CINAHL’s subject heading list will help maintain the descriptors in selected NRCS categories.
The NRCS identifies the necessary data elements to generate an index for studies in the “Registry of Nursing Research,” organized by variable name so that the index lists all studies in which a particular variable is examined.
Conclusion
The development of the Sigma Theta Tau International Nursing Research Classification System (NRCS) has greatly enhanced the organization and retrieval of nursing research. The NRCS facilitates comparison, analysis, and indexing of nursing studies, providing a robust framework for categorizing research knowledge. As the system continues to evolve, it will play a crucial role in advancing nursing science, promoting best practices, and ensuring that nursing research is easily accessible and applicable to the clinical environment.