COMPASSS

Comparative Research Designs (1st ECPR Virtual Summer School)
2020-07-27 - 2020-07-31 | Online
This course provides training on methods that enable a researcher to construct a solid and well-argued comparative research design (CRD) – any research enterprise that comprises at least two ‘cases’ or units of analysis.
We will cover multiple options, from very few cases (small-n) to multiple cases (intermediate-n) to many cases (larger-n).
By the end of this course, you will be able to write up a well-constructed CRD section for your project and to reflect strategically on your comparative research project.
Key topics covered
We will cover a logical sequence of topics that constitute the core building blocks of a solid CRD:

Thinking upstream: why go comparative? What is the added value of comparison? What should be the mindset of a good comparative researcher? What is the link between a research puzzle and the choice for a CRD? How to formulate a comparative research question?
‘Casing’ operations: what are my cases, how to define them, conceptually and empirically? At which level(s) (micro, meso, macro) can they be apprehended? And what about the time dimension?
Which case selection strategy to choose? How many cases and which ones? Should I go ‘smaller-n’ or ‘larger-n’? Should I select cases with similar or different outcomes? Which basic case selection strategies are available, and what are the pros and cons? And what about more advanced strategies, e.g. ‘nested’ (multilevel) designs, designs including multiple time periods, etc?
How to systematically collect good-quality data when covering multiple cases? What are the tricks of the trade? How to gain sufficient ‘intimacy’ with the respective cases (case-based-knowledge)? And how to compile and manage this data?
How to engage in comparative data analysis? Which toolbox(es) to select, among ‘qualitative’ (case-oriented), specifically comparative (in particular QCA – Qualitative Comparative Analysis), and ‘quantitative’ (statistical, variable-oriented) data analysis techniques?

We’ll unpack topics 1, 2 and 3 in detail, and take a bird’s eye view of topics 4 and 5 because they refer to multiple methods and techniques (and multiple specialised – including many courses in weeks 2 and 3 of the 1st ECPR Virtual Methods School).
This seminar-type course provides a highly interactive online teaching and learning environment, using state of the art online pedagogical tools. It is designed for a demanding audience (researchers, professional analysts, advanced students) and capped at a maximum of 12 participants so that the Instructor can cater to the specific needs of each individual.
Prerequisite Knowledge
Little prior knowledge is expected. Any training in qualitative and/or quantitative methods would be an asset, but is by no means a requirement. You should simply be willing to reflect openly about your research design – there is no ‘best’ or ‘one-size-fits-all’ comparative research design.

Complexity, Organizations, and Grand Challenges (36th EGOS Colloquium)
2020-07-02 - 2020-07-04 | University of Hamberg, Hamberg, 20146, Germany
Managers and organizational scholars are increasingly being called on to deal with “grand challenges” and “wicked problems,” including issues such as poverty, public health, and climate change, to name but a few. One of the hallmarks of such grand challenges is their complexity, for as the EGOS Colloquium 2020 theme notes, they involve “an array of potential dilemmas, paradoxes, complexities, contradictions, and conflicts”. Such complexity is challenging and often surprising in both its nature and its consequences. Their interdependencies mean that the outcomes of attempts to solve such challenges are often unexpected and difficult to predict and may give rise to new issues elsewhere.
Likewise, managers who care about impactful results have realized that the path forward remains unclear. Existing data frequently offers a dizzying array of suggestions. Each suggestion may have merit and some may be more valuable than others. Yet, many suggestions may only work in combination or “conjunction” with others. A combination of a few tactics may be more effective than either a piecemeal approach that prioritizes only one strategy or a shotgun approach that tries everything.
Clearly, the complex challenges that societies and organizations currently face require nuanced and powerful theorizing. Yet, many of our current approaches – both theoretically and empirically – are not able to account for this kind of complexity. Thus, organizational scholars need to develop novel avenues of critical thinking, innovative and creative theories, and methodologies capable of translating creative theories into corresponding empirical models. In recent years, researchers have aimed to account for such complexity with a theoretical shift toward understanding phenomena in a configurational manner (Fiss et al., 2013; Misangyi et al., 2016). At the same time, corresponding methodological developments have aimed at tackling causal complexity, most prominently the emergence of a set-analytic perspective (Ragin, 1987, 2000, 2008; Fiss, 2007, 2011). These developments present more than a resurgence of configurational thinking or a new methodological approach – they suggest the emergence of a neo-configurational perspective, a perspective that aims to understand social and organizational phenomena in set-theoretic terms, allowing for an analysis of specific causal complexities.
In the current sub-theme, we aim to start a conversation about how this neo-configurational perspective offers opportunities to disentangle complex social and organizational challenges. Specifically, we would like to open up a dialogue about how a deeper engagement with complexity and the use of a neo-configurational perspective may reshape ways of theorizing organization; how we empirically engage with our data to understand the rich and complicated relationships that characterize organizational life; and how scholars may leverage causal complexity to advance research on grand challenges, wicked problems, and beyond.
We invite papers that contribute to a configurational understanding and welcome contributions from multiple theoretical fields of organizational studies. We encourage theoretical, empirical, and methodological contributions that strive to enhance our ability to capture causal complexity and the dynamic nature of configurations. We especially welcome papers deploying set-theoretic methods such as crisp and fuzzy set Qualitative Comparative Analysis (QCA) and related set-analytic and configurational approaches, but also work using case studies, process tracing, and other empirical approaches for advancing our scholarly understanding of causal complexity.
Our sub-theme particularly invites contributions that focus on one or more of the following questions:

Theoretical Connections: How does a neo-configurational perspective challenge existing theories on grand challenges? How can set-theoretic methods deepen existing theories or integrate different aspects of existing theories such as institutional theories, resource dependency theories, and others?
Methodological Innovation: What new methodological tools do we need to disentangle causal complexity? How can we make the methodological toolkit more robust and complementary? On what assumptions are set-theoretic methods and QCA based and how can we assess/test these assumptions? What are the limits of set-theoretic methods?
Empirical Findings: We welcome original empirical applications of QCA in different fields of organizational studies (CSR, corporate governance and sustainability, strategy, sustainable entrepreneurship, human resources, etc.).
The Role of Organizations: What role, specifically, do organizations play in dealing with the challenges of today, both grand and small? How can organizations help us overcome complexity? Conversely, what is the role of complexity in (and of) organizations?
Uncovering (Category) Intersectionality: One central feature of grand challenges is the interconnected nature of social categorizations (e.g., the trade-offs among social, environmental and economic categories in the triple bottom line.) How can a neo-configurational perspective help us understand systems of reinforcing advantages and disadvantages?
Institutional Complexity: How might a neo-configurational perspective help us understand incompatible prescriptions from multiple institutional logics? What can it contribute to studying constellations of institutional logics?
Complex Organizational Forms: After a century of classic organizational forms and structures, new ways of organizing emerge, such as organizational networks, virtual and hybrid organizations. How can a neo-configurational perspective clarify the processes and the complex conditions that make these forms (in-)effective?
Theorizing Hybridity: Complexity can weaken difference in type, suggesting the existence of hybrid solutions or recombination instead of discrete categories and positions. How do we theorize such organizational hybridity and fuzzy organizational boundaries?

References

Fiss, P.C. (2007): “A set-theoretic approach to organizational configurations.” Academy of Management Review, 32 (4), 1180–1198.
Fiss, P.C. (2011): “Building better causal theories: A fuzzy set approach to typologies in organizational research.” Academy of Management Journal, 54 (2), 393–420.
Fiss, P.C., Cambré, B., & Marx, A. (eds.) (2013): Configurational Theory and Methods in Organizational Research. Research in the Sociology of Organizations, Vol. 38. Bingley: Emerald Group Publishing Ltd.
Misangyi, V.F. (2016): “Institutional complexity and the meaning of loose coupling: Connecting institutional sayings and (not) doings.” Strategic Organization, 14 (4), 1–34.
Ragin, C.C. (1987): The Comparative Method: Moving Beyond Qualitative and Quantitative Strategies. Berkeley: University of California Press.
Ragin, C.C. (2000): Fuzzy-Set Social Science. Chicago: University of Chicago Press.
Ragin, C.C. (2008): Redesigning Social Inquiry: Fuzzy Sets and Beyond. Chicago: University of Chicago Press.

Qualitative Comparative Analysis
2020-06-01 - 2020-06-03 | Online
Qualitative Comparative Analysis (QCA) is a method that has become part of the toolbox in disciplines such as political science, sociology, public administration and organization and management studies. QCA can be used to answer any research question if one is interested in analyzing patterns of necessity and sufficiency in a group of cases, ranging from a handful to many thousands. This course introduces participants to the principles and techniques of Qualitative Comparative Analysis (QCA) on a methodological and an applied dimension. At the end of the course, participants will be familiar with the key elements of a QCA study and know how to read, criticize, and implement an empirical analysis.
Software: We will use R within RStudio, both of which are freely available. It is recommended that participants be familiar with RStudio and basic commands. Participants who want to acquire basic R programming skills, or need to refresh them, should take an introductory R course, or should access an online tutorial in advance of the course. Before the course starts, I will share basic information on online tutorials and the entire R code that I will use for illustrating QCA.
Prerequisites: Basic knowledge of QCA and set-theoretic thinking is useful, but not necessary, for taking the course.

Southern California QCA Workshop - CANCELED DUE TO CORONAVIRUS
2020-03-26 - 2020-03-28 | Central European University – Vienna, Quellenstraße 51, Vienna, Wien, 1100, Austria
The goal of this workshop is to provide a ground-up introduction to Qualitative Comparative Analysis (QCA) and fuzzy sets. Participants will get intensive instruction and hands-on experience with the fsQCA software package and on completion should be prepared to design and execute research projects using the set-analytic approach.
Update: The workshop has been canceled due to the Coronavirus pandemic

ECPR Methods School: Advanced Topics in Set-Theoretic Methods and QCA
2020-02-17 - 2020-02-21 | University of Bamberg, Kapuzinerstraße 16, Bamberg, D-96047, Germany
This course addresses advanced issues that arise if and when scholars embrace notions of sets and their relations. While it is a course about set-theoretic methods writ large, most of the time, we will discuss issues specific to QCA. We will try and address all the following topics but, depending on participants’ needs and interests, we can put more emphasis on some: set-theoretic multi-method research; robustness and sensitivity; set-theoretic theory evaluation; enhanced Standard Analysis; data structures and set-theoretic methods, including temporal ordering and two-step QCA; model ambiguity; multi-value QCA.

ECPR Methods School: Introduction to Qualitative Comparative Analysis (QCA)
2020-02-17 - 2020-02-21 | University of Bamberg, Kapuzinerstraße 16, Bamberg, D-96047, Germany
This course introduces participants to crisp set and fuzzy set Qualitative Comparative Analysis (QCA) and its analysis in R. It provides participants with a basic understanding of the analytic underpinnings and steps of QCA, and enables them to independently perform a basic crisp or fuzzy set QCA (Standard Analysis). We will look at the origins, analytic aims, and variants of QCA, and deal in depth with techniques and practices of set calibration. The nuts and bolts the QCA technique, from parameters of fit to all steps of the analyses of necessity and sufficiency, are illustrated based on an empirical example study which we replicate in class. We will then cover the presentation and interpretation of QCA results, as well as ways to deal with limited diversity and other potential pitfalls. Hands-on exercises and daily lab sessions provide opportunities for practice and engagement.

ECPR Methods School: Foundations of set-theoretic and case-oriented methods
2020-02-14 - 2020-02-15 | University of Bamberg, Kapuzinerstraße 16, Bamberg, D-96047, Germany
This course introduces participants to the logic and foundations of case-oriented and set-theoretic methods. We discuss perspectives on causality, case-orientation in empirical social research, and the main features of set-theoretic methods. We will reflect about different types of research questions, evidence and observations, causal complexity, causal effects, causal mechanisms, and context. The course then covers basics of set theory, measurement and set calibration, logical operations, and the logic of necessary and sufficient conditions as set relations. We will apply these notions by looking at different ways of defining, structuring, and operationalizing concepts and cases. We look at different areas of application.

ECPR Seasoned Scholar Workshop: Multi-Method Designs, Case-Oriented and Comparative Methods
2020-02-13 - 2020-02-15 | University of Bamberg, Kapuzinerstraße 16, Bamberg, D-96047, Germany
This Workshop is tailored for scholars with significant research experience beyond their PhD, and organised on a flexible basis to meet specific needs — typically in connection with an ongoing research project they are managing (e.g. troubleshooting, arbitrating between methodological options, fine-tuning some designs, etc. It covers a broad range of case-oriented methods and designs (single case studies, process tracing, ‘thick’ binary comparisons, etc…), comparative methods and designs (small-N comparisons, intermediate-N comparison across multiple cases, Qualitative Comparative Analysis (QCA) and neighbouring methods, typology-building, etc.), and ‘mixed’/multi-methods designs combining qualitative, comparative and/or quantitative methods.

International Winter School on Public Policy - Alps Edition 2020: Qualitative Comparative Analysis (QCA)
2020-01-06 - 2020-01-10 | Rotterdam School of Management, Erasmus University, Burgemeester Oudlaan 50, Rotterdam, PA, 3062, Netherlands
Qualitative Comparative Analysis (QCA) is a set-theoretic method for identifying necessary and/or sufficient conditions for outcomes which is increasingly used in comparative policy analysis. Its core advantages lie in modelling causal complexity and enabling systematic comparisons to identify regularities, while integrating case knowledge at all levels of analysis. This course introduces participants to the nuts and bolts of QCA and its implementation using the most powerful currently available software in R. Apart from basic knowledge of empirical social research design and methodology, no particular pre-existing knowledge is required.

3rd International QCA Paper Development Workshop 2019
2019-12-11 | ETH Zürich, Rämistrasse 101, Zurich, Switzerland
The International QCA Paper Development Workshop 2019 (ETH Zurich, Wednesday/Thursday, 11./12. December 2019) provides a unique platform for researchers working on papers involving QCA to meet QCA experts, get feedback on their on-going research, and learn about the latest methodological developments in QCA. The workshop is interdisciplinary and interactive and allows for in-depth discussions and individual feedback from internationally renowned QCA scholars.
We invite submission of abstracts from researchers applying QCA in various domains (e.g., sociology, political science, management, evaluation studies, international relations, medicine, and health) as well as policy and business consultants using QCA in their work.

7th International QCA Expert Workshop
2019-12-10 - 2019-12-11 | ETH Zürich, Rämistrasse 101, Zurich, Switzerland
The 7th International QCA Expert Workshop provides a venue for experienced QCA researchers to discuss the latest and most important developments around QCA. The workshop focuses exclusively on methodological and conceptual advances around QCA, not on applications of QCA in empirical research. We expect all participants to actively participate in the program. In order to allow for active participation among researchers with diverse academic backgrounds, the number of participants is limited. If you’re working on a project which you think might fit to the workshop, please contact Johannes Meuer.

The 7th International QCA Expert Workshop will take place after the Paper Development Workshop. Please note that because the Expert Workshop serves a different purpose, targets a different audience, and – for these reasons – is purposefully limited in the number of participants, participation in the 7th International QCA Expert Workshop is by invitation only. If you are applying QCA in one of your research projects, please see the International QCA Paper Development Workshop.

Pre-Conference Workshop on Coincidence Analysis (12th Annual Conference on the Science of Dissemination & Implementation in Health)
2019-12-04 14:30 - 16:00 (America/New_York) | Crystal Gateway Marriott (Arlington, VA), 1700 Jefferson Davis Hwy, Arlington, Virginia, 22202
This workshop will introduce Coincidence Analysis (CNA), a relatively new member within the family of Configurational Comparative Methods. CNA is specifically designed to analyze causal complexity, which is common in implementation research. Presenters will discuss the types of studies for which CNA is useful, provide worked examples of applying CNA to datasets, and share practical resources for using CNA. Participants will learn how CNA works through hands-on exercises involving Boolean algebra, the bottom-up algorithm used by CNA and model performance measures like coverage.

Training Day: Fuzzy Set Qualitative Comparative Analysis (fsQCA)
2019-10-25 09:00 - 17:00 (Europe/London) | Cathie Marsh Institute for Social Research (University of Manchester), Oxford Road, Manchester, M13 9PL, United Kingdom
Qualitative Comparative Analysis is a systematic method of studying data on multiple comparable cases from about N=8 through to large datasets of N=10,000 etc. The QCA methods firstly involve casing, i.e. delineating cases; secondly organising a systematic data matrix (we will show these in NVIVO and in Excel); thirdly examining sets of cases known as configurations; fourth interpreting these in terms of ‘necessary cause’ and ‘sufficient cause’ of each major outcome of interest. We demonstrate the fsQCA software for QCA. A fuzzy set is a record of the membership score of a case in a characteristic or set. A crisp set is a membership value of 0 (not in the set) or 1 (fully in the set), and thus is a simplified measure compared with a fuzzy set. Fuzzy sets or crisp sets, and combinations can be used in QCA. All the permutations of the causal factors, known as X variates, are considered one by one. We test whether X is necessary, or sufficient, or both, for an outcome Y. We then augment the standard measures of ‘consistency’. We show that one can generate both within-group and sample-wide consistency levels for testing sufficient cause.
This one-day training course will attract those doing case-study research, those doing comparative research, and those who want to extend their skills in fuzzy set analysis from beginner to intermediate levels. It will suit qualitative as well as quantitative and mixed-methods researchers; all are welcome.

Qualitative Comparative Analysis (QCA) in Research on Environment, Conflict, and Peace
2019-10-23 09:00 - 13:30 (America/Los_Angeles) | Central European University – Vienna, Quellenstraße 51, Vienna, Wien, 1100, Austria
A training on QCA will be organised by Charles Ragin and Tobias Ide during the First Environmental Peacebuilding Conference (October 23-25, University of California Irvine). The training will be held from 9:00-1:30 at October 23 and provide an introduction to QCA with a focus on applications in the field of environmental security and environmental peacebuilding.

Short Course on Qualitative Comparative Analysis, 23rd Swiss Summer School in Social Science Methods
2019-08-19 - 2019-08-23 | Università della Svizzera Italiana, Via Buffi 13, Lugano, 6900, Switzerland
The course provides participants with a thorough introduction to Qualitative Comparative Analysis (QCA), both as a research approach and as a data analysis technique. In recent years, this set-theoretic method has gained recognition among social scientists as a methodological approach that holds specific benefits for comparative studies. The course begins by familiarizing participants with the foundations of set theory and the basic concepts of the methodological approach of QCA, including necessary and sufficient conditions, Boolean algebra, and fuzzy logic. The next step is devoted to the calibration of empirical data into crisp and fuzzy sets. Once these essentials are in place, the course moves on to the construction and analysis of truth tables as the core of the QCA procedure. Here, we will also spend time to discuss typical challenges that arise during a truth table analysis, and techniques to overcome such problems. Finally, the course will introduce consistency and coverage as parameters of fit, as well as additional measures to assess the robustness of QCA results.
Besides the technical introduction of QCA and its variants, the course will provide opportunities to discuss general aspects of comparative research design, including criteria for concept building and case selection, and data-related issues. Participants will be given the opportunity to present their own work and to receive individual feedback on their projects.
Throughout the course, participants will conduct set-theoretic analyses within the R software environment (packages “QCA” and “SetMethods”). The software will be introduced on the first day and used for exercises and examples throughout the course, so that participants gain a level of proficiency that enables them to conduct their own QCA analyses upon the completion of the course. Participants are encouraged to bring their own qualitative and/or quantitative data for course exercises (if available, preliminary data is fine). In addition, datasets from published studies will be made available and used for in-course exercises.

Panel on Case-Oriented and Set-Theoretic Approaches to Comparative Policy Analysis, 4th International Conference on Public Policy (ICPP4)
2019-06-26 - 2019-06-28 | University of Concordia, Montreal, Canada
Recent years have seen an impressive proliferation of set-theoretic and case-oriented methods in comparative policy analysis in general (see e.g. Rihoux et al. 2011; Thomann 2019), and in policy implementation and evaluation research in particular (Gerrits and Verweij 2018; Pattyn et al. 2017). Case-oriented and set-theoretic approaches to comparative policy analysis, including but not limited to methods such as Qualitative Comparative Analysis (QCA), Coincidence Analysis (CNA, explanatory typologies, and comparative process tracing, are designed to address the challenges of contemporary policy analysis. Situated within a “critical realist” paradigm of social research (Gerrits and Verweij 2013), they model different aspects of causal complexity, such as the prevalence of configurations of different factors leading to policy outputs or outcomes, equifinality (multiple policy strategies or instruments resulting in the same outcome), contextual contingencies, and causal asymmetry. Moreover, they can be applied within a variety of small-N or large-N research approaches to evaluate as well as generate theories through a combination of systematic comparison with targeted in-depth case studies (Thomann and Maggetti 2017).
This panel gathers theoretical, conceptual, and empirical contributions by both junior and senior scholars that deal with case-oriented and set-theoretic approaches and illustrate their potential and limitations to contribute to the theory and practice of policy analysis. We particularly invite contributions that either comprehensively review or systematize the state of the art, apply methodological innovations to empirical settings, connect methods with theories, and/or contribute to methodological innovation themselves. Papers should engage in a critical reflection of methodological aspects and their connection with the theory and/or practice of policy analysis in general, or implementation and evaluation in particular. Abstracts should include a clear puzzle, research question, outline of the approach, research design, and main contribution of the proposed paper. Preference is given to abstracts that demonstrate an understanding of recent methodological developments.

ICPSR Summer Program in Quantitative Methods of Social Research
2019-06-17 - 2019-06-19 | University of Michigan, Ann Arbor, MI, United States
QCA can be used to answer any research question if one is interested in analyzing patterns of necessity and sufficiency in a group of cases ranging from a handful to many thousands. The method is now widely used in different disciplines including political science, sociology, public administration, public health, medical research, organization and management research.
The course introduces participants to the principles and techniques of Qualitative Comparative Analysis (QCA) on a methodological and an applied dimension using RStudio. At the end of the course, participants will be familiar with the key elements of a QCA study and know how to read, criticize and implement an empirical analysis.

Designing Research with Qualitative Comparative Analysis (QCA)
2019-06-10 - 2019-06-14 | University of Exeter, Penryn Campus, Exeter, Devon, United Kingdom
This module introduces you to the nuts and bolts of Qualitative Comparative Analysis (QCA), an innovative set-theoretic technique that allows for comparisons of small, intermediate or large numbers of cases in order to identify necessary and / or sufficient conditions for an outcome. It is an attractive method for scholars who seek to model causally complex patterns and integrate in-depth case knowledge at all stages of the analysis. We will introduce you to performing QCA with the freely available R software using the user-friendly RStudio environment.

QCA: Origin, variants, uses and approaches
Set theory and causal complexity
Defining, structuring, measuring and calibrating concepts as sets
Analyses of necessity and sufficiency
Truth tables, limited diversity and counterfactual reasoning
Conservative, intermediate and parsimonious solution types
Set-theoretic multi-method research
Potential pitfalls (skewed data, model ambiguities, robustness, etc.)

Comparative Case Study Design
2019-06-03 - 2019-06-07 | University of Exeter, Penryn Campus, Exeter, Devon, United Kingdom
Description: This module provides you with the skills needed to design your qualitative case study research. It covers concept formation, casing and case selection, logics and strategies of comparison, accounting for context and time, data collection strategies, and both conceptual and research-practical issues such as limited diversity, Galton’s problem, conceptual stretching, and thinking about scope conditions. In the lab sessions, we will work extensively with you on your own research projects.

The logic and goals of qualitative comparative case study research
Defining, structuring and measuring social science concepts and typologies
Casing: what is a case? What is context?
Case selection and scope conditions
Logics and techniques of comparison across time and space

2nd International QCA Summer Workshops
2019-05-22 - 2019-05-24 | Prague University of Economics and Business, Czech Republic, Czech Republic
The 2nd International QCA Summer Workshops consist of a sequence of three workshops: an Advanced applications workshop (22 May) in which users with at least intermediate-level knowledge of QCA receive more advanced feedback on their work-in-progress from QCA experts; (2) an invitation-only Expert workshop (23 May) gathering QCA experts and developers so as to make progress on some QCA innovation fronts; (3) a Paper development workshop (24 May) in which early-stage users receive expert guidance on their first QCA application.
Besides the three workshops: two parallel, two-day (22-23 May) modular doctoral courses will be offered: an Introduction to QCA doctoral course for participants with no prior QCA training, and an Intermediate-level QCA doctoral course for participants with some prior level of QCA training or practice. In addition, there will be also a specific half-day session for consultants (23 May).

Southern California QCA Workshop
2019-03-28 - 2019-03-30 | Central European University – Vienna, Quellenstraße 51, Vienna, Wien, 1100, Austria
The goal of this workshop is to provide a ground-up introduction to Qualitative Comparative Analysis (QCA) and fuzzy sets. Participants will get intensive instruction and hands-on experience with the fsQCA software package and on completion should be prepared to design and execute research projects using the set-theoretic approach.
