03 · What You Need to Know
Theoretical Scope Has Several Dimensions
Broad and narrow are relative to the research question
A theory cannot be classified as universally too broad or too narrow.
A broad sociocultural theory may be entirely appropriate for a study examining how individual practices are embedded within institutional and cultural systems. The same theory may be unnecessarily expansive for a study testing one specific cognitive mechanism.
Likewise, a tightly focused behavioral theory may be ideal for predicting one decision but inadequate for a question about how organizational structures, social norms, and individual agency interact.
The relevant comparison is therefore not theory versus some ideal size. It is theory versus research question.
Scope is not simply the number of constructs
A theory with ten constructs is not automatically broader than one with four.
Theoretical scope can involve several dimensions: what phenomenon the theory explains, the level or levels of analysis at which it operates, the populations or settings to which it is intended to apply, the time scale it assumes, the mechanisms it proposes, and the outcomes it attempts to explain.
Recent guidance on theory selection similarly emphasizes matching theory to the theoretical entity being investigated and clarifying scope conditions such as level, context, and time.
A relatively simple theory may therefore make very broad claims, while a theory containing many constructs may operate within a tightly defined domain.
A theory may be too broad if most of it is irrelevant to your question
Suppose a theory explains individual learning through interactions among personal, behavioral, environmental, social, and developmental processes. Your research question concerns only a specific relationship between one belief and one learning behavior.
The theory may still contain the relationship you need, but adopting the entire theoretical architecture could create unnecessary obligations. You might find yourself explaining constructs and propositions that never appear again in the research design.
This is one reason researchers do not always need to use an entire theory. A theoretically coherent subset may be sufficient when the research question concerns only part of a broader explanation.
A theory may be too broad if you cannot translate it into research decisions
Highly abstract theories can provide intellectually powerful perspectives while offering limited guidance for a particular empirical design.
Ask what the theory changes in your study. Does it identify relevant constructs? Suggest relationships or mechanisms? Shape sampling or observation? Provide concepts for interpretation?
If the theory operates at such a high level of abstraction that you cannot explain how it connects with the evidence you will collect, you may need an intermediate framework, a more focused theory, or a clearer account of how abstract concepts will be translated into the study.
The problem is not abstraction itself. The problem is an unexplained jump from abstract theory to specific evidence.
A theory may be too broad if it shifts the study away from its original problem
Theory should sharpen a research problem, not replace it with a larger one.
Imagine that you begin with a question about how doctoral students evaluate the credibility of AI-generated academic information. You select a broad theory concerned with knowledge, identity, social interaction, institutional authority, and cultural practice.
If applying the theory requires the study to investigate all of these dimensions when your actual question concerns credibility judgment, theoretical breadth may be driving unnecessary scope expansion.
This is a warning sign that the framework is determining the project rather than helping answer its question.
A theory may be too narrow when a central mechanism falls outside it
The opposite problem occurs when a theory explains only one part of what the research question asks.
Suppose you want to understand why instructors with similar attitudes toward generative AI behave differently under different institutional policies. A theory focused exclusively on individual attitudes may explain variation in personal intention but offer little account of institutional constraint.
If institutional conditions are central to the research question, this is not a peripheral omission. The theory may be too narrow for the explanatory task.
You could then consider another theory, multiple perspectives, or a broader conceptual framework rather than pretending that an individual-level theory explains an institutional process.
Level of analysis is a major source of mismatch
Theories make assumptions about where explanation occurs.
Some theories concern individuals. Others explain relationships among groups, organizations, institutions, societies, or systems. Still others explicitly connect levels.
A theory can therefore be topically relevant but analytically mismatched.
For example, a theory explaining individual intention may be relevant to technology adoption, but it cannot automatically explain why universities establish different AI policies. The phenomenon is related, but the level of explanation has changed.
Recent theory-selection guidance specifically recommends clarifying the level of analysis and scope conditions when matching theory to a research problem.
Boundary conditions help define whether the theory reaches your context
Theories are not expected to explain everything everywhere.
Boundary conditions identify circumstances under which theoretical propositions are expected to apply or change. These may involve populations, cultures, institutional environments, technologies, historical periods, or other contextual conditions.
A theory developed around voluntary behavior, for instance, may have uncertain applicability when behavior is mandatory. A theory developed around stable technologies may operate differently when the technology changes rapidly.
Do not immediately conclude that the theory is too narrow simply because your setting is new. Ask whether features of the new setting alter the mechanism or assumptions on which the theory depends.
A narrow theory can be a strength
Researchers sometimes prefer broader theories because they appear more comprehensive.
But explanatory precision often requires limits.
A narrow theory may specify one mechanism clearly, make distinguishable predictions, and define the conditions under which those predictions should hold. For a focused research question, that can be more useful than a broad theory capable of accommodating many possible outcomes.
Recent methodological work on comparative theory testing similarly emphasizes theories with clear mechanisms and empirically distinguishable implications rather than arguments so broad that they become difficult to challenge.
Theoretical narrowness is therefore not synonymous with theoretical weakness.
A broad theory can also be a strength
Broad theories become valuable when the phenomenon itself spans several mechanisms, contexts, or levels.
If your research asks how educational technology practices emerge from interactions among individual beliefs, professional communities, institutional policies, and broader cultural expectations, a narrowly individual theory may fragment the phenomenon unnecessarily.
A broader perspective can reveal connections that a highly focused explanation misses.
The key is whether your research design can meaningfully engage that breadth. A theory may fit the phenomenon conceptually but still exceed what one empirical study can investigate.
Do not confuse theoretical scope with study scope
A theory can be broader than the study without being inappropriate.
You may use only the portion relevant to your research question. The problem arises when you imply that your study examines or tests the entire theory even though it investigates only a small part.
Theory scope
The range of phenomena, constructs, mechanisms, levels, contexts, and conditions the theory is intended to explain.
Study scope
The particular questions, population, setting, constructs, evidence, and relationships examined in your research.
A well-designed theoretical framework creates a defensible bridge between the two.
A theory that is too narrow may need extension rather than replacement
Suppose a theory explains the central phenomenon well but fails under one identifiable condition.
You do not necessarily need to abandon it.
The mismatch may reveal a boundary condition or missing mechanism that provides an opportunity to extend or refine the existing theory.
This response is appropriate when the theory's central explanatory logic remains useful and the limitation can be specified theoretically.
If the theory misses most of what the research question requires, however, repeated extension may become a sign that another framework would be more appropriate.
A theory that is too narrow may require a second perspective
Some research problems genuinely cross explanatory domains.
An individual-level theory might explain motivation while an organizational theory explains institutional constraints. If the question concerns their interaction, neither theory may be sufficient independently.
Using more than one theory can then be defensible, provided each perspective has a distinct role.
Do not add theories merely to ensure that every possible variable has theoretical ancestry. The additional perspective should address something central that the first theory cannot.
Parsimony matters, but simplicity is not the only criterion
A useful theory should not contain unnecessary explanatory machinery, but choosing the smallest theory available is not automatically good theory selection.
Recent theory-selection guidance includes parsimony alongside matching, applicability, conceptual rigor, testability, and the capacity to generate worthwhile insight.
This matters because theoretical fit is multidimensional. A very simple theory that omits the phenomenon's central mechanism may be less useful than a somewhat broader theory that captures it.
The goal is sufficient explanation without unnecessary theoretical baggage.
Watch Out
Do not choose a theory because its diagram has approximately the same number of boxes as your proposed model. Theoretical scope concerns what the theory explains, at what level, under what assumptions, and within what boundaries. Diagram size is a poor proxy.
The right fit should survive the “why this theory?” question
Imagine a reviewer asking why you selected this theory rather than a broader or narrower alternative.
A strong answer should connect the theory to the research question, phenomenon, level of analysis, explanatory mechanism, and intended contribution.
“It has been widely used in similar studies” establishes precedent but not necessarily fit.
“It explains the specific mechanism our research question examines, operates at the appropriate level of analysis, and does not require constructs outside the scope of the study” is considerably stronger.
This is ultimately part of choosing a theory without forcing one to fit.
