Process tracing is a

research Research is "creative and systematic work undertaken to increase the stock of knowledge". It involves the collection, organization and analysis of evidence to increase understanding of a topic, characterized by a particular attentiveness ...

method used to develop and test theories. It is generally understood as a "within-case" method to draw inferences on the basis of causal mechanisms. It has been used in

social sciences Social science is one of the branches of science, devoted to the study of societies and the relationships among individuals within those societies. The term was formerly used to refer to the field of sociology, the original "science of so ...

(such as in psychology), as well as in

natural sciences Natural science is one of the branches of science concerned with the description, understanding and prediction of natural phenomena, based on empirical evidence from observation and experimentation. Mechanisms such as peer review and repeat ...

. Scholars that use process tracing evaluate the weight of evidence on the basis of the strength of tests (notably straw-in-the-wind tests, hoop tests, smoking gun tests, double decisive tests). As a consequence, what matters is not solely the quantity of observations, but the quality and manner of observations. By using

Bayesian probability Bayesian probability is an interpretation of the concept of probability, in which, instead of frequency or propensity of some phenomenon, probability is interpreted as reasonable expectation representing a state of knowledge or as quantification ...

, it may be possible to make strong causal inferences from a small sliver of data through process tracing. As a result, process tracing is a prominent

case study A case study is an in-depth, detailed examination of a particular case (or cases) within a real-world context. For example, case studies in medicine may focus on an individual patient or ailment; case studies in business might cover a particular fi ...

method.

Process tracing

Process-tracing can be used both for inductive (theory-generating) and deductive (theory-testing) purposes. In terms of theory-testing, the process-tracing method works by presenting the observable implications (

hypotheses A hypothesis (plural hypotheses) is a proposed explanation for a phenomenon. For a hypothesis to be a scientific hypothesis, the scientific method requires that one can test it. Scientists generally base scientific hypotheses on previous obse ...

) of a theory, as well as alternative explanations that are inconsistent with the theory. Once these observable implications are presented, they are then tested empirically to see which of the observable implications can be observed and which cannot. Process-tracing emphasizes the temporal sequence of events, and requires fine-grained case knowledge. Stephen Van Evera's influential typology of process-tracing tests distinguishes tests depending on how they adjudicate between theoretical expectations: * Straw-in-the-wind tests: Failure or passage of this test neither lends strong support for or against the theory * Hoop tests: Failure to pass a hoop test can be disqualifying for a theory but passing the hoop test does not necessarily lend strong support for the theory * Smoking gun tests: Passing a smoking gun test lends strong support for theory, whereas failure does not necessarily lend strong support against the theory * Double decisive tests: Passing a double decisive test lends strong support for the theory while also lending strong support against alternative theories It is often used to complement comparative case study methods. By tracing the causal process from the independent variable of interest to the dependent variable, it may be possible to rule out potentially

intervening variable In statistics, a mediation model seeks to identify and explain the mechanism or process that underlies an observed relationship between an independent variable and a dependent variable via the inclusion of a third hypothetical variable, known as ...

s in imperfectly matched cases. This can create a stronger basis for attributing causal significance to the remaining independent variables. A limitation to process-tracing is the problem of

infinite regress An infinite regress is an infinite series of entities governed by a recursive principle that determines how each entity in the series depends on or is produced by its predecessor. In the epistemic regress, for example, a belief is justified bec ...

. While some influential works by methods scholars have argued that the ability of process-tracing to make causal claims is limited by low

degrees of freedom Degrees of freedom (often abbreviated df or DOF) refers to the number of independent variables or parameters of a thermodynamic system. In various scientific fields, the word "freedom" is used to describe the limits to which physical movement or ...

, methodologists widely reject that the "degrees of freedom" problem applies to research that uses process-tracing, given that qualitative research entails different logics than quantitative research (where scholars do need to be wary of degrees of freedom). One advantage to process-tracing over quantitative methods is that process-tracing provides inferential leverage. In addition to aiding uncovering and testing causal mechanisms, process-tracing also contributes descriptive richness. By assigning probabilities to outcomes under specific conditions, scholars can use Bayesian rules in their process tracing to draw robust conclusions about the causes of outcomes. For example, if a scholar's theory assumes that a number of observable implications will happen under certain conditions, then the repeated occurrence of those outcomes under the theorized conditions lends strong support for the scholar's theory because the observed outcomes would be improbable to occur in the manner expected by the scholar if the theory were false. By using Bayesian probability, it may be possible to make strong causal inferences from a small sliver of data. For example, a video recording of a person committing a bank robbery can be very strong evidence that a particular person committed the robbery while also ruling out that other potential suspects did it, even if it is only a single piece of evidence. Scholars can also use

set theory Set theory is the branch of mathematical logic that studies sets, which can be informally described as collections of objects. Although objects of any kind can be collected into a set, set theory, as a branch of mathematics, is mostly concern ...

in their process tracing.

Process tracing

See also

References

Further reading