Shawna K Metzger
Biographic Data
| ID | 4122642 |
|---|---|
| NAME | Shawna K Metzger |
| GIVEN NAMES | Shawna K |
| FAMILY NAME | Metzger |
| SIGNATURE | METZGER S K |
| AFFILIATIONS | National University of Singapore |
| ORCID | 0000-0003-1087-9621 |
| VERIFIED | Yes |
| TOTAL WORKS | 13 |
| TOTAL CITATIONS | 44 |
| AUTHOR COUNT | 13 |
| EDITOR COUNT | 0 |
| FIRST PUBLICATION YEAR | 2015 |
| LATEST PUBLICATION YEAR | 2025 |
| H-INDEX | 4 |
Out of order
The Cox duration model serves as the basis for more complex duration models like competing risks, repeated events, and multistate models. These models make a number of assumptions, many of which can be assessed empirically, sometimes for substantive ends. We use Monte Carlo simulations to show the order in which practitioners assess these assumptions can impact the model’s final specification, and ultimately, can produce misleading inferences. We…
Calendar versus Analysis Time
Previous work in International Studies Quarterly shows higher levels of humanitarian aid prolong civil conflicts. It also finds, among conflict–years in which aid is received, that this conflict-prolonging effect is more acute in insurgency-based civil conflicts, albeit with weaker supporting evidence. However, I show this work accidentally generated its conflict duration variable incorrectly, with the duration measuring time since January 1, 196…
Implementation Matters
Political scientists commonly use Grambsch and Therneau’s (1994, Biometrika 81, 515–526) ubiquitous Schoenfeld-based test to diagnose proportional hazard violations in Cox duration models. However, some statistical packages have changed how they implement the test’s calculation. The traditional implementation makes a simplifying assumption about the test’s variance–covariance matrix, while the newer implementation does not. Recent work suggests t…
Proportionally Less Difficult
Keele (2010, Political Analysis 18:189–205) emphasizes that the incumbent test for detecting proportional hazard (PH) violations in Cox duration models can be adversely affected by misspecified covariate functional form(s). In this note, I reevaluate Keele’s evidence by running a full set of Monte Carlo simulations using the original article’s illustrative data-generating processes (DGPs). I make use of the updated PH test calculation available i…
Getting Time Right
Logit and probit (L/P) models are a mainstay of binary time-series cross-sectional (BTSCS) analyses. Researchers include cubic splines or time polynomials to acknowledge the temporal element inherent in these data. However, L/P models cannot easily accommodate three other aspects of the data’s temporality: whether covariate effects are conditional on time, whether the process of interest is causally complex, and whether our functional form assump…
Teaching Econometrics Dynamically with R-Shiny
An abstract is not available for this content so a preview has been provided. Please use the Get access link above for information on how to access this content
Different Words, Same Song
The use of duration models in political science continues to grow, more than a decade after Box-Steffensmeier and Jones (2004). However, several common misconceptions about the models still persist. To improve scholars’ use and interpretation of duration models, we point out that they are a type of regression model and therefore follow the same rules as other more commonly used regression models. In this article, we present four maxims as guideli…
Within or between jobs? Determinants of membership volatility in the European Parliament, 1979–2014
This paper uses duration analysis to model determinants of early exit for all members of the European Parliament (MEPs), 1979–2014, and compares this with existing accounts of between-session turnover in the EP. The notable diversity present in the national political and electoral institutions of the 28 member states electing MEPs allows us to maximize purchase over both cross-national and temporal sources of variation found in the EP. Our findin…
Evaluating Conflict Dynamics
Interest in processes has become increasingly pronounced in international conflict research in recent years, especially how these processes unfold across time “dynamics”. We focus in particular on “stage conceptions” of dynamics: processes that unfold over a series of sequential, and possibly recurrent, stages. We suggest that stage conceptions have two key properties: plurisectality and conditional covariate effects. We propose a novel econometr…
The Chicken or the Egg
Is state behavior influenced by the context in which it occurs, or does context arise because of the way in which states behave? I investigate these questions in the context of international disputes over issues and states’ militarized behavior. The prevalent assumption in interstate conflict research is that disputed issues are exogenous to militarization patterns. I question the validity of this assumption, arguing there are reasons to suspect …
Surviving Phases
Many political processes consist of a series of theoretically meaningful transitions across discrete phases that occur through time. Yet political scientists are often theoretically interested in studying not just individual transitions between phases, but also the duration that subjects spend within phases, as well as the effect of covariates on subjects’ trajectories through the process's multiple phases. We introduce the multistate survival mo…
Time is on my side? The impact of timing and dispute type on militarized conflict duration
What influences the duration of interstate militarized conflicts? I argue that duration is affected by when the militarization occurs in the overarching dispute. Further, I suggest that the type of dispute being fought over has a conditioning effect. I hypothesize that later-occurring militarizations will last longer, but only in disputes over territorial issues. I test my argument on a sample of militarized conflicts over territorial, maritime, …
Screening Out Risk
Do intergovernmental organizations (IGOs) screen out conflict-prone states? We argue that IGOs have incentives to guard against admitting new members that pose significant security risks. Using a data set based on state–IGO pairings, we find clear evidence of screening: As security risk increases, the probability of IGO membership declines. Our findings underscore the importance of accounting for possible selection bias when studying the effects …
Surviving Phases
Many political processes consist of a series of theoretically meaningful transitions across discrete phases that occur through time. Yet political scientists are often theoretically interested in studying not just individual transitions between phases, but also the duration that subjects spend within phases, as well as the effect of covariates on subjects’ trajectories through the process's multiple phases. We introduce the multistate survival mo…
Within or between jobs? Determinants of membership volatility in the European Parliament, 1979–2014
This paper uses duration analysis to model determinants of early exit for all members of the European Parliament (MEPs), 1979–2014, and compares this with existing accounts of between-session turnover in the EP. The notable diversity present in the national political and electoral institutions of the 28 member states electing MEPs allows us to maximize purchase over both cross-national and temporal sources of variation found in the EP. Our findin…
Screening Out Risk
Do intergovernmental organizations (IGOs) screen out conflict-prone states? We argue that IGOs have incentives to guard against admitting new members that pose significant security risks. Using a data set based on state–IGO pairings, we find clear evidence of screening: As security risk increases, the probability of IGO membership declines. Our findings underscore the importance of accounting for possible selection bias when studying the effects …
Evaluating Conflict Dynamics
Interest in processes has become increasingly pronounced in international conflict research in recent years, especially how these processes unfold across time “dynamics”. We focus in particular on “stage conceptions” of dynamics: processes that unfold over a series of sequential, and possibly recurrent, stages. We suggest that stage conceptions have two key properties: plurisectality and conditional covariate effects. We propose a novel econometr…
Getting Time Right
Logit and probit (L/P) models are a mainstay of binary time-series cross-sectional (BTSCS) analyses. Researchers include cubic splines or time polynomials to acknowledge the temporal element inherent in these data. However, L/P models cannot easily accommodate three other aspects of the data’s temporality: whether covariate effects are conditional on time, whether the process of interest is causally complex, and whether our functional form assump…
Proportionally Less Difficult
Keele (2010, Political Analysis 18:189–205) emphasizes that the incumbent test for detecting proportional hazard (PH) violations in Cox duration models can be adversely affected by misspecified covariate functional form(s). In this note, I reevaluate Keele’s evidence by running a full set of Monte Carlo simulations using the original article’s illustrative data-generating processes (DGPs). I make use of the updated PH test calculation available i…
Teaching Econometrics Dynamically with R-Shiny
An abstract is not available for this content so a preview has been provided. Please use the Get access link above for information on how to access this content
Implementation Matters
Political scientists commonly use Grambsch and Therneau’s (1994, Biometrika 81, 515–526) ubiquitous Schoenfeld-based test to diagnose proportional hazard violations in Cox duration models. However, some statistical packages have changed how they implement the test’s calculation. The traditional implementation makes a simplifying assumption about the test’s variance–covariance matrix, while the newer implementation does not. Recent work suggests t…
The Chicken or the Egg
Is state behavior influenced by the context in which it occurs, or does context arise because of the way in which states behave? I investigate these questions in the context of international disputes over issues and states’ militarized behavior. The prevalent assumption in interstate conflict research is that disputed issues are exogenous to militarization patterns. I question the validity of this assumption, arguing there are reasons to suspect …
Time is on my side? The impact of timing and dispute type on militarized conflict duration
What influences the duration of interstate militarized conflicts? I argue that duration is affected by when the militarization occurs in the overarching dispute. Further, I suggest that the type of dispute being fought over has a conditioning effect. I hypothesize that later-occurring militarizations will last longer, but only in disputes over territorial issues. I test my argument on a sample of militarized conflicts over territorial, maritime, …
Screening Out Risk
Do intergovernmental organizations (IGOs) screen out conflict-prone states? We argue that IGOs have incentives to guard against admitting new members that pose significant security risks. Using a data set based on state–IGO pairings, we find clear evidence of screening: As security risk increases, the probability of IGO membership declines. Our findings underscore the importance of accounting for possible selection bias when studying the effects …
The Chicken or the Egg
Is state behavior influenced by the context in which it occurs, or does context arise because of the way in which states behave? I investigate these questions in the context of international disputes over issues and states’ militarized behavior. The prevalent assumption in interstate conflict research is that disputed issues are exogenous to militarization patterns. I question the validity of this assumption, arguing there are reasons to suspect …
Surviving Phases
Many political processes consist of a series of theoretically meaningful transitions across discrete phases that occur through time. Yet political scientists are often theoretically interested in studying not just individual transitions between phases, but also the duration that subjects spend within phases, as well as the effect of covariates on subjects’ trajectories through the process's multiple phases. We introduce the multistate survival mo…
Within or between jobs? Determinants of membership volatility in the European Parliament, 1979–2014
This paper uses duration analysis to model determinants of early exit for all members of the European Parliament (MEPs), 1979–2014, and compares this with existing accounts of between-session turnover in the EP. The notable diversity present in the national political and electoral institutions of the 28 member states electing MEPs allows us to maximize purchase over both cross-national and temporal sources of variation found in the EP. Our findin…
Evaluating Conflict Dynamics
Interest in processes has become increasingly pronounced in international conflict research in recent years, especially how these processes unfold across time “dynamics”. We focus in particular on “stage conceptions” of dynamics: processes that unfold over a series of sequential, and possibly recurrent, stages. We suggest that stage conceptions have two key properties: plurisectality and conditional covariate effects. We propose a novel econometr…
Different Words, Same Song
The use of duration models in political science continues to grow, more than a decade after Box-Steffensmeier and Jones (2004). However, several common misconceptions about the models still persist. To improve scholars’ use and interpretation of duration models, we point out that they are a type of regression model and therefore follow the same rules as other more commonly used regression models. In this article, we present four maxims as guideli…
Teaching Econometrics Dynamically with R-Shiny
An abstract is not available for this content so a preview has been provided. Please use the Get access link above for information on how to access this content
Getting Time Right
Logit and probit (L/P) models are a mainstay of binary time-series cross-sectional (BTSCS) analyses. Researchers include cubic splines or time polynomials to acknowledge the temporal element inherent in these data. However, L/P models cannot easily accommodate three other aspects of the data’s temporality: whether covariate effects are conditional on time, whether the process of interest is causally complex, and whether our functional form assump…
Proportionally Less Difficult
Keele (2010, Political Analysis 18:189–205) emphasizes that the incumbent test for detecting proportional hazard (PH) violations in Cox duration models can be adversely affected by misspecified covariate functional form(s). In this note, I reevaluate Keele’s evidence by running a full set of Monte Carlo simulations using the original article’s illustrative data-generating processes (DGPs). I make use of the updated PH test calculation available i…
Calendar versus Analysis Time
Previous work in International Studies Quarterly shows higher levels of humanitarian aid prolong civil conflicts. It also finds, among conflict–years in which aid is received, that this conflict-prolonging effect is more acute in insurgency-based civil conflicts, albeit with weaker supporting evidence. However, I show this work accidentally generated its conflict duration variable incorrectly, with the duration measuring time since January 1, 196…
Implementation Matters
Political scientists commonly use Grambsch and Therneau’s (1994, Biometrika 81, 515–526) ubiquitous Schoenfeld-based test to diagnose proportional hazard violations in Cox duration models. However, some statistical packages have changed how they implement the test’s calculation. The traditional implementation makes a simplifying assumption about the test’s variance–covariance matrix, while the newer implementation does not. Recent work suggests t…
Out of order
The Cox duration model serves as the basis for more complex duration models like competing risks, repeated events, and multistate models. These models make a number of assumptions, many of which can be assessed empirically, sometimes for substantive ends. We use Monte Carlo simulations to show the order in which practitioners assess these assumptions can impact the model’s final specification, and ultimately, can produce misleading inferences. We…
Computer Science (9 works) · Econometrics (8 works) · Economics (8 works) · Mathematics (8 works) · Political Conflict and Governance (8 works) · Electoral Systems and Political Participation (6 works) · Political science (6 works) · Covariate (5 works) · Duration (music (5 works) · International Relations and Foreign Policy (5 works)