Statistics, Politics and Policy

@sppjournal.bsky.social

Applying statistical analysis to (public) policy: https://www.degruyter.com/journal/key/spp/html

What drives Indonesia’s defense spending? How do economic and regional factors shape it? In issue 1/2026, Muchamad Bachtiar, Bambang Irwanto, Irdam Ahmad, Zainal Abidin Sahabuddin, and Trismadi Trismadi analyze Indonesia’s defense spending using an ARDL model. Read more: doi.org/10.1515/spp-...

Defense Spending Under Pressure: An ARDL Study of Indonesia’s Economic and Strategic Realities

This study examines the economic and geopolitical determinants of Indonesia’s defense expenditure from 1984 to 2022 using the Autoregressive Distributed Lag (ARDL) model to capture both short-term and long-term dynamics. Recognizing the contextual relevance of Indonesia’s Total People’s Defense and Security System (SISHANKAMRATA), the analysis relies on conventional military expenditure data (% of GDP) due to the absence of consolidated multi-ministerial records. The results show that in the short run, defense spending is highly sensitive to macroeconomic shocks: inflation, exchange rate volatility, and foreign direct investment exert negative effects, while debt, trade openness, and regional military expenditure strengthen budgetary allocations. In the long run, macroeconomic fundamentals (debt, growth, inflation, and foreign investment) together with neighboring countries’ military spending drive defense expenditure, whereas regional average spending has a negative effect and U.S. military expenditure does not show a structural impact. These findings underscore the dual pressures of fiscal fragility and regional security competition in shaping Indonesia’s defense budget. Policy implications highlight the importance of inflation-adjusted and exchange rate–resilient budgeting, sustainable financing mechanisms such as defense bonds or a Defense Sovereign Wealth Fund (D-SWF), and deeper ASEAN defense cooperation to balance security needs with fiscal discipline. This study contributes a macro-level perspective on defense economics under conditions of institutional fragmentation, offering a framework for future comparative and panel-based research across decentralized security systems.

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Which demographic groups are most at risk for rapid Tuberculosis onset? In issue 3/2025, Ernest Zamanah and Suleman Nasiru employ a Bayesian framework to analyze Tuberculosis cases in the Bolgatanga Municipality, Ghana. Read more: doi.org/10.1515/spp-...

Bayesian Analysis of Tuberculosis Cases in Bolgatanga Municipality, Ghana–West Africa

Tuberculosis (TB) represents a major threat to global health security and is currently the world most deadly infectious disease. TB is noted to affect people of all age groups and exposure to the disease has been shown to exhibit variation in the risk of infection across different factors. This study was therefore carried out to identify possible disease associations of some risk factors in relation to time until onset of TB among TB infected individuals in the Bolgatanga Municipality of the Upper East Region of Ghana. To this end, secondary data on time until onset of TB was obtained from the Bolgatanga Regional Hospital of the Upper East Region of Ghana and used for statistical analysis. In order to obtain appropriate underlying disease associations, the Bayesian approach to the modelling of survival time was employed in the statistical analyses. Thus, different parametric models including; skew normal, lognormal, shifted lognormal, exponential, Weibull and Fréchet models were fitted to the TB data within the Bayesian framework. The Weibull was the overall best fitted model. Based on the estimation results of the Bayesian Weibull regression model; individuals with no education, individuals with diabetes and males were identified as high-risk groups with shorter time frame for the onset of TB in the Bolgatanga Municipality. The study was concluded by indicating the need for Ghana Health Service to institute targeted interventions aimed at preventing and controlling the TB with special emphasis to the high-risk groups in the Bolgatanga Municipality.

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What are key drivers of political instability in West Africa? In issue 3/2025, Richard Gbemudia and Stanley Akachukwu highlight GDP per capita, military expenditure, and unemployment as decisive factors to explain why only some ECOWAS nations experienced coups. Read more: doi.org/10.1515/spp-...

Determinants of Political Instability in ECOWAS (1991–2022)

This study examined GDP per Capita, military expenditure, trade openness capital formation, inflation and unemployment as determinants of political instability in ECOWAS from 1991 to 2022. Four countr...

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In issue 1/2025, Muchamad Bachtiar, Irdam Ahmad, Zainal Abidin Sahabuddin, and Trismadi Trismadi conduct a meta-analysis of military expenditure determinants across 15 studies. They find war, ongoing spending, and external threats to be key drivers - while national conditions correlate negatively.

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In issue 1/2025, Osafu Augustine Egbon and Ezra Gayawan present a spatio-temporal model of violent conflict and fatalities in Nigeria. Using a Cox point process and SPDE approach, they analyze georeferenced conflict data to identify regional patterns and high-risk areas.

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In our issue 1/2025, Aaron Cooke and John Vivian develop a restricted data-rich dynamic factor model to evaluate vaccination efficacy during the 2020 coronavirus pandemic. Their model can be used for other populations, as they provide an open-source Python package.

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In issue 1/2025, John O’Reilly proposes the County-Elector Plan to revitalize the Electoral College. Implementable by states, it would avoid a constitutional change and future gerrymandering. Thereby, electoral competition would be shifted from a few battleground states to several hundred counties.

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What drives GDP growth in Ghana? Emmanuel Amoako Koranteng, Gideon Mensah Engmann, and Dioggban Jakperik apply a hierarchical Bayesian model to analyze key macroeconomic variables in our issue 3/2024: real exchange rates, manufacturing, and government expenditure positively impact GDP growth.

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Declining U.S. influence, particularly in Asia, and rising Chinese engagement: in their contribution to our issue 3/2024, Elizabeth G., Steven Kim, Nicholas Sobrepena, Stone Goethe, and Eric E. analyze media coverage across 96 African and Asian nations and find geopolitical influence.

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How can we better predict municipal solid waste? In issue 3/2024, Chellai Fatih explores the power of hybrid modeling techniques to forecast municipal solid waste (MSW) generation across OECD countries. The article's findings highlight the need for data-driven waste management policies.

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How predictable are election outcomes? In issue 3/2024, Richard J. Heggen and Alfred G. Cuzán develop a geometric model to analyze 1,825 elections across five federal democracies. The model incorporates the rate of incumbency decay and predicts election outcomes within a 2–3 point margin.

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Can Voting Advice Applications (VAAs) capture party relations? In our issue 3/2024, Felix Wieland analyzes data from 63 editions of the German Wahl-O-Mat to track party proximities. His findings suggest that design changes have significantly altered measured proximities between major parties.

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Talknice Saungweme, Glenda Maluleke, and Nicholas M. Odhiambo of the University of South Africa use a nonlinear autoregressive distributed lag model to study the impact of financial development on Mauritius' economic growth. The results reveal an asymmetric relationship between the two.

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Marwah S. Siam, Hussein A. Sayed, and Laila O. El-Zeini of Cairo University apply a mixture-function mortality model to examine lifespan length and variation in Egypt from 1950 to 2021. The study reveals increasing longevity and a declining variation in age at death over time.

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Addressing the pension conundrum, Gustavo De Santis of Università di Firenze explores a novel approach, called IPAYGO. Including demographic and economic challenges, like differential mortality and low fertility rates, IPAYGO offers a sustainable and equitable approach to pensions.

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The impact of an aging electorate on democratic processes is at the core of Christopher-David Preclik's introduction of "political adultism". He describes "the socially-accepted interpersonal, structural, and institutional discrimination of young and younger people in politics".

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