03 · What You Need to Know
What Makes Evidence and Research Empirical?
Empirical refers to knowledge grounded in observation or experience
At its core, empirical concerns what can be learned through observation, experience, or evidence about the world rather than solely through abstract reasoning.
In scientific research, empirical evidence may come from experiments, measurements, surveys, observations, interviews, fieldwork, records, documents, images, behavioral traces, or other systematically examined sources. What counts as appropriate empirical evidence depends on the phenomenon and methodology.
The National Research Council's discussion of scientific research emphasizes the primacy of empirical testing and the use of well-codified observational methods in scientific inquiry, while also recognizing deductive proof in mathematics as a different basis for warranted knowledge claims.
Empirical research does not mean experimental research
Experiments generate empirical evidence because researchers observe what happens under deliberately manipulated conditions. But experimentation is only one route to empirical evidence.
An epidemiologist analyzing naturally occurring disease patterns is conducting empirical research. So is an ecologist recording species behavior, a sociologist conducting interviews, or an education researcher analyzing classroom observations.
None of these studies becomes non-empirical simply because the researcher did not manipulate an independent variable.
This is one reason research does not have to involve an experiment. Observation can be empirical without being experimental.
Empirical research can be quantitative
Quantitative empirical research represents relevant observations numerically. Researchers may measure variables, estimate distributions, compare groups, model associations, evaluate predictions, or estimate effects.
A survey estimating the prevalence of academic burnout is empirical because its conclusions are based on systematically collected observations from respondents. An experiment measuring learning outcomes is empirical. A study analyzing national employment records is empirical even when the researcher did not collect those records personally.
Statistics may be important for analyzing such evidence, but statistics do not make the research empirical. The observations do.
Empirical research can also be qualitative
Suppose researchers conduct in-depth interviews with teachers about how they respond to generative AI in student assessment. The interviews are observations of participants' accounts generated through interaction with the researchers. Systematic analysis of those accounts can constitute empirical research.
Ethnographic field notes, observations of social interactions, interview transcripts, diaries, documents, and other qualitative materials can likewise provide empirical evidence when they are examined systematically within an appropriate methodology.
Therefore, the distinction between empirical and non-empirical research should not be confused with the distinction between quantitative and qualitative research. As explained in whether research has to use statistics, qualitative inquiry can be fully empirical without using conventional statistical analysis.
Empirical data do not have to be collected specifically for the current study
Another common misunderstanding equates empirical research with primary data collection. Existing evidence can remain empirical.
A researcher analyzing census records is working with observations about a population. A researcher using an existing longitudinal dataset is analyzing empirical data even though another research team collected them. A historian examining archival documents may be working systematically with surviving evidence about past events.
The origin of the data and the empirical character of the evidence are different questions. This is why research can use existing data without collecting new observations.
Empirical evidence is not simply “anything you can find”
The existence of observations does not automatically make an empirical claim strong. Evidence must be relevant to the question and generated, selected, measured, or interpreted appropriately.
If researchers want to estimate university students' average study time, asking three conveniently available friends produces empirical observations, but those observations may provide a very weak basis for a population estimate.
Likewise, observing that two events occur together does not automatically establish causation. Empirical evidence acquires meaning through research design, measurement, context, and reasoning.
This is why being empirical and being rigorous are different characteristics. A study can unquestionably use empirical data and still be methodologically weak.
Empirical observations are shaped by measurement and interpretation
The phrase "let the data speak for themselves" is appealing but incomplete. Data do not arrive as perfectly neutral representations of reality.
Researchers decide what to observe, how to operationalize concepts, which instruments to use, what counts as a case, how variables are coded, what questions participants are asked, and how ambiguous evidence is interpreted. Instruments themselves have limitations. Categories can embed assumptions.
Recognizing this does not make empirical research arbitrary. It means researchers should make consequential methodological choices explicit and subject them to scrutiny.
The relationship between evidence and the researcher's perspective becomes especially important when considering whether research can ever be completely objective.
Observation can be direct or mediated through instruments and records
Empirical research does not require researchers to observe a phenomenon with their unaided senses.
Scientists routinely rely on microscopes, telescopes, sensors, imaging systems, laboratory instruments, standardized assessments, digital platforms, databases, and computational pipelines. Such tools extend what can be observed and measured.
The evidence remains empirical, but researchers must understand the instruments and processes through which it was produced. Calibration, validity, measurement error, data processing, and provenance can all affect what the resulting observations mean.
Empirical research can be descriptive without testing a hypothesis
Researchers may collect empirical evidence simply to characterize a phenomenon accurately. A study might estimate the distribution of a disease, document biodiversity within an ecosystem, describe patterns of technology use, or systematically observe classroom interactions.
Such studies can make valuable empirical contributions even when they do not begin with a directional hypothesis. Observation is not scientifically meaningful only after it has been recruited into hypothesis testing.
This is another reason the idea of one mandatory scientific-method sequence can be misleading. Scientific investigation can move among observation, exploration, hypothesis development, testing, modeling, and revision in different ways.
Theory and empirical evidence perform different but connected functions
Empirical research does not operate without ideas. Researchers need concepts and theories to decide what questions matter, what should be measured, which relationships deserve investigation, and how findings might be interpreted.
Theory can generate predictions that empirical research tests. Empirical findings can support, refine, challenge, or motivate theories. Sometimes observations reveal patterns for which existing theories provide inadequate explanations.
Empirical work
Develops or evaluates claims through systematic engagement with observational or experiential evidence.
Theoretical work
Develops, formalizes, integrates, or examines explanations, models, concepts, or propositions, sometimes without generating new empirical observations.
The distinction does not imply that theoretical work ignores evidence or that empirical work lacks theory. Strong research often depends on interaction between the two.
Some legitimate scholarship is not primarily empirical
Whether all research must be empirical depends partly on how broadly research is being defined and on the scholarly field.
Mathematics provides a clear example. Mathematical knowledge can be established through deductive proof rather than empirical observation. The National Research Council explicitly distinguishes empirical evidence in scientific inquiry from deductive proof in mathematics when discussing warranted knowledge claims.
Philosophical research may develop arguments through conceptual analysis and logical reasoning. Some theoretical work develops formal models or conceptual frameworks without collecting new empirical data. Legal and humanities scholarship may rely on forms of textual, interpretive, historical, or normative reasoning that do not map neatly onto the empirical-science model.
Whether particular traditions describe their materials as empirical varies, so broad claims that all scholarship either is or is not empirical can quickly become terminological rather than illuminating.
Scientific claims are generally expected to remain answerable to empirical evidence
Within empirical science, explanations ultimately need some connection to observable evidence. A theory that generates no possible empirical consequences is difficult to evaluate scientifically.
This does not mean every individual scientific paper must collect new data. Theoretical scientists may develop models that organize existing evidence or generate predictions for future empirical testing. Methodologists may develop analytical techniques. Researchers may synthesize previously collected empirical studies.
The broader scientific enterprise connects these activities to observation through cycles of theory development, empirical testing, confirmation, correction, and revision.
Empirical does not mean unquestionably true
Calling a finding empirical tells you something about the basis of the claim. It does not certify the quality of the evidence or the correctness of the conclusion.
An empirical study can contain measurement error, sampling bias, confounding, poor analysis, selective reporting, inappropriate interpretation, or other weaknesses. Two empirical studies can reach different conclusions.
The National Academies emphasizes that scientific confidence emerges through multiple lines of examination rather than through treating any individual result as definitive. Even rigorously conducted research can fail to replicate.
Empirical evidence therefore needs critical evaluation, not reverence.
“Evidence-based” and “empirical” are related but not interchangeable
An empirical study generates or analyzes observational evidence. An evidence-based decision, by contrast, generally involves using relevant available evidence to guide a choice, often together with contextual considerations, expertise, values, resources, or other factors depending on the field.
A practitioner can make an evidence-based decision by consulting empirical research without personally conducting an empirical study. Conversely, an empirical study can be too weak or irrelevant to provide a good basis for a particular decision.
Keeping these concepts separate prevents the word empirical from becoming a generic synonym for "credible."
