Podcast Summary: Verena Halsmayer on Managing Growth in Miniature: Solow’s Model as an Artifact

Podcast: New Books Network – Peoples and Things
Host: Lee Vinsel
Guest: Verena Halsmayer
Date: November 24, 2025

Episode Overview

This episode explores Verena Halsmayer's award-winning book, Managing Growth in Miniature: Solow’s Model as an Artifact. Halsmayer, a postdoctoral scholar at the University of Vienna, discusses the iconic Solow growth model and its role not just as a theory but as a practical tool and a product of its scientific and institutional milieu. The conversation delves into how economic reasoning, especially around growth and technological change, emerged, stabilized, and spread through the work of Robert Solow and his peers. Halsmayer emphasizes the cultural, material, and practical dimensions of economic modeling and traces the afterlives and ironies of the Solow model in policy, teaching, and development.

Key Discussion Points and Insights

The Book’s Intent and Approach

• Understanding Economic Reasoning as Practice

  • Halsmayer aims “to better understand economic reasoning,” focusing not just on economy theories or ideas, but on how these are rooted in “historically specific and culturally framed practice that is done with specific tools” ([04:43]).
  • She brings a historian of science perspective, considering modeling and measurement as practices, not simply abstract ideas.

• Importance of the Solow Model

  • The Solow growth model is credited with explaining economic growth and the importance of technological progress. However, Halsmayer interrogates what "explaining growth" and "technological progress" actually mean in the context of economic reasoning ([08:49]).
  • The Solow model formalized a certain style of economic reasoning—mathematical modeling—that became dominant between the 1930s and 1960s ([06:21]).

What Is the Solow Growth Model?

• Model Features

  • Presents a “self-sustaining economic equilibrium” via a simple mathematical formula—a frictionless world assuming full employment, perfect competition, and perfect foresight ([08:49]).
  • Key finding: population growth and capital investment alone can't account for growth rates; the residual is attributed to technological change ([08:49–13:16]).

• The “Solow Residual”

  • When the model is deployed empirically, the gap between input and output growth becomes the “Solow residual” or “Total Factor Productivity” (TFP)—labeled technological progress, though it captures everything not explained by the model, including “social, political, cultural factors, and measurement errors” ([14:52–15:43]).
  • Memorable moment: “Technology was just the label put on the residual, on the rest.” — Verena Halsmayer ([15:06])

Models as Tools and Practices

• Method and Theoretical Framing

  • Halsmayer draws from philosophers and historians such as Mary Morgan, Marcel Boumans, and Harold Moss, looking at models as artifacts and practices ([17:12]).
  • Her approach moves beyond “doctrine” to investigate "specific intellectual cultures, social worlds...research and teaching, institutional and material conditions" ([24:37], [25:41]).

• Teaching and Disciplinary Norms

  • The Solow model is not just a research tool but a teaching device: “if you want to be an economist, this is how you do it” ([27:00]).
  • Robert Solow at MIT was seen as “the teacher,” emphasizing collegiality and open workshop culture ([27:20]).

Performativity, Policy, and the Life of Models

• Performativity vs. Interventionist Knowledge

  • While related to performativity literature (i.e., models shaping reality), Halsmayer is more focused on “how the problem of growth was constituted through the model,” and the model’s unintended afterlives ([29:37]).
  • Models can develop a life of their own, sometimes leading to regret among their creators ([31:01]).

• Interventionist Knowledge

  • Halsmayer co-edited a special issue on “interventionist knowledge,” examining how social science tools informed post-war policy across states, businesses, and organizations ([32:00–33:43]).
  • One of the ironies: models or knowledge devices are often used in ways “other than intended, led to different outcomes than expected, or was simply ignored” ([33:43]).

The Book's Structure and Solo’s Place in the Story

• Halsmayer intentionally avoids a hero biography of Solow, focusing sparsely on him as a person ([34:17–35:50]).
• Tracking the model’s place among “parallel constructions”—Solow’s became dominant, but she resists simplifying into hero/villain narratives ([35:45], [38:09]).

The Model’s Flexibility and Political Afterlives

• Interpretive Ambiguity

  • The Solow model’s very abstractness and simplicity made it widely adaptable—and ambiguous. It “could be interpreted in a variety of different ways,” making it a vehicle for both state-driven and market-driven policy ([49:13–53:50]).
  • Quote: “A model is ambiguous enough that you can kind of project your uses and desires...and use it for your ends.” — Lee Vinsel ([53:27])

• Policy Device and Knowledge Infrastructures

  • The model became embedded in macroeconomic forecasting, planning models, and policy evaluation even as the details changed ([54:36–57:41]).
  • “It’s not only about the acceptance of a specific theory...but really about the hegemony of a specific kind of problematization through the tools and infrastructures of knowledge.” — Verena Halsmayer ([57:41])

• Political Ironies

  • Salo’s model is sometimes directly associated with neoliberalism, but in fact, its politics are “far from obvious”—it has served many different projects and worldviews ([67:53–69:07]).
  • Halsmayer’s focus: “It’s the politics of the knowledge” ([68:21]).

The Model and Technology Studies

• Computerization and Modeling
  • Halsmayer addresses the crossover between economics and computing—Solow’s is a “sweet, sweet exercise in comparison” to computationally more complex input-output models ([62:18–63:21]).
  • She traces empirical labor: transforming raw industrial data into usable model form ([63:52–64:42]).
  • Shift: From rich, discursive documentation of empirical problems (e.g., NBER) to the dominant style of mathematical abstraction with little methodological transparency ([64:44]).

Current and Future Work

• From Economic Planning to Alternative Planning
  • Halsmayer is now researching “alternative economic planning,” specifically the Lucas Plan (1975–82), an industrial worker initiative for socially useful production in the UK ([74:23–76:34]).
  • Focus: How knowledge, calculation, and participatory planning technologies moved across domains, aiming to show that alternative forms of organizing production could also be economically viable.

Notable Quotes & Memorable Moments

• On Economic Models as Practice:
  “I think what is most important to me was to not think of economists’ knowledge as a set of theories or ideas, but rather as a practice, like historically specific and culturally framed practice that is done with specific tools.” — Verena Halsmayer ([04:43])

• On the Solow Residual:
  “Technology was just the label put on the residual, on the rest.” — Verena Halsmayer ([15:06])

• On Teaching the Model:
  “If you want to be an economist, this is how you do it.” — Verena Halsmayer ([27:00])

• On Interpretive Flexibility:
  “A model is ambiguous enough that you can kind of project your uses and desires...and use it for your ends.” — Lee Vinsel ([53:27])

• On Political Complexity of the Model:
  “It is one additional small-scale storyline of market thinking that maybe tones down a little the break of the 1970s in that it focuses on the tenacity and resilience of governmental knowledge infrastructures… the sources of neoliberal governance are not only the ideas of the big names…” — Verena Halsmayer ([69:07])

• On Ongoing Measurement Debates:
  “You can see the computer age everywhere but in the productivity statistics.” — (After Solow’s famous quip, cited at [72:27])

Important Timestamps

• [04:43] — Verena summarizes the book’s purpose and approach to economic reasoning.
• [08:49–13:16] — Explaining the Solow Model and Solow Residual.
• [14:52–15:43] — What “technology” actually means in the model.
• [17:12] — Influence of historians of science and philosophy, rubric of “models as artifacts.”
• [27:00] — The Solow model’s role in teaching economics.
• [29:37–33:43] — Models, performativity, and interventionist knowledge.
• [34:17–35:50] — Decision not to make the book a biography of Solow.
• [49:13–53:50] — Ambiguity of the model, “carrier” for divergent political could-be’s.
• [57:41] — The persistence of knowledge infrastructures and models.
• [67:53–69:07] — Ironies, politics, and the model’s adoption.
• [74:23–76:34] — Halsmayer introduces her research into the Lucas Plan and alternative planning.

Final Thoughts

This episode offers a richly layered exploration of how economic thinking is shaped, taught, and institutionalized, using the Solow growth model as a lens. Halsmayer’s work complicates the triumphalist or villainous readings of economics’ “great men” and their models by highlighting the practices, ambiguities, and unforeseen consequences in the long afterlife of a paradigm. The conversation is interspersed with personal and professional anecdotes, careful attention to the materiality of knowledge, and a humility regarding the ongoing limits of economic measurement—a perfect listen for anyone interested in economics, science studies, or the politics of expertise.