Hi! Welcome to my page!
I’m Kien, a Research Fellow at the
Centre for Care, ESRC Research Centre.
My work spans applied data science, health economics, and climate and environmental economics,
with a focus on institutional analysis and policy evaluation.
Methodologically, I work with causal inference (DiD/event study/RCT),
econometrics, machine learning, large language models, including text-as-data
applications, topic modeling, and forecasting for policy and risk analysis.
Research Interests
- Health Economics
- Sociology and Social Policy
- Environmental Economics
- Financial Economics
- Applied Data Science
- Monetary Policy
Education
-
PhD in Economics (University of Birmingham)
Oct 2021 – Dec 2025
-
MA in Economic Development (Erasmus University Rotterdam)
Oct 2013 – Oct 2015
-
Postgraduate certificate (Monash University)
Jan 2021 - Jul 2021
Working
Papers
Improving Staff Retention at the RBFT – Econometric Data Analytics,
Probabilistic Forecasting and Management Intelligence
Status: Ongoing project
Abstract
In this project, we develop and evaluate forecasting models to predict the probability
of staff leaving the Royal Berkshire NHS Foundation Trust (RBFT) over horizons ranging
from one to twelve months. We begin with conventional predictive models to identify
key determinants of staff turnover and progressively implement advanced
machine-learning approaches to enhance predictive performance.
The final Balanced Random Forest models perform strongly across all forecasting
horizons. At the 12-month horizon, the model achieves approximately 99.7% overall
accuracy, recall close to 100%, and precision of around 96%, correctly identifying
nearly all future leavers while maintaining a low false-positive rate. Performance
remains similarly robust at the 6-month horizon, with precision around 90% and recall
close to 100%.
In line with management priorities, we also implement forecasting under a
two-month notice-period setting, reflecting typical RBFT practice. Under this
configuration, the model attains approximately 99.6% accuracy and around 94% precision,
correctly flagging more than 99% of staff who subsequently leave. Cross-validation
and expanding-window testing confirm that model performance remains stable and robust
over time.
The resulting framework functions as a practical early-warning system for staff
retention. By identifying at-risk employees in advance, managers can intervene earlier,
target support effectively, and reduce recruitment and training costs.
Co-authors: Shixuan Wang; Rita Fontinha
Words to the Wise: Do Green Bonds and Language Make an Impact on Greenness?
Status: Empirical work complete
Abstract
We examine whether corporate green bond issuance causally reduces firms’
greenhouse gas (GHG) emissions intensity and whether linguistic structure
shapes this environmental impact. Using an unbalanced panel of 3,867
publicly listed non-financial firms across 65 countries (2010–2024),
we implement a staggered Difference-in-Differences design, complemented
by entropy balancing to strengthen comparability between treated and
control firms.
We find that green bond issuance leads to economically meaningful
emission reductions of approximately 19–21% on average. The effects
are stronger in carbon-intensive industries, among high-investment
firms, and for long-maturity bonds, suggesting real operational
adjustments rather than symbolic commitments.
Crucially, we document a novel moderation channel: firms headquartered
in countries with weak Future Time Reference (FTR) languages experience
significantly larger emission reductions following issuance. This
linguistic effect remains robust when using a CEO-level Weak-FTR index
constructed via machine-learning-based phonetic classification. Our
findings demonstrate that financial instruments and cultural-linguistic
structures jointly shape corporate environmental outcomes.
Co-authors: Alessandra Guariglia
When Birds of Different Feathers Flock Together: Ethnic Diversity and Armed Conflict
Status: Empirical work complete · Target: Personality and Social Psychology Bulletin (CABS 4)
Abstract
Ethnic diversity is frequently debated as either a structural source of instability
or a foundation for long-term social resilience. However, existing research largely
relies on static correlations and provides limited insight into how sudden increases
in diversity affect conflict dynamics over time. Using panel data for 152 countries
from 1990–2013, we conceptualize entry into the top quintile of the Historical Index
of Ethnic Fractionalization (HIEF) as an exogenous diversity “shock” and estimate its
dynamic effects on intra-state armed conflict.
We find clear causal evidence that diversity shocks increase conflict intensity.
Following a shock, conflict dyads rise significantly and remain elevated for
approximately six years before gradually attenuating. This dynamic escalation–adaptation
pattern constitutes a novel contribution to the literature, which has not previously
clarified the temporal adjustment process following large shifts in ethnic composition.
Mechanism analyses reveal substantial heterogeneity across regions and development levels.
The effect is most pronounced in Asia and the Middle East, moderate in the Americas
and Europe, and weaker elsewhere. Countries with lower Human Development Index (HDI)
levels experience stronger post-shock conflict escalation, while higher-HDI societies
demonstrate faster stabilization. Diversity shocks are also associated with higher
conflict-related mortality rates, indicating effects not only on incidence but also
on intensity.
Our findings remain robust across two-way fixed-effects models, staggered
difference-in-differences event studies, regression discontinuity designs around
the diversity threshold, and alternative panel specifications. By isolating the
dynamic shock component of ethnic diversity, our study clarifies when and where
diversity destabilizes societies and how institutional capacity shapes subsequent
adaptation.
Co-authors: Miguel R. Ramos; Matt Bennett; Unaysah Mogra
Funded
Research
Projects
-
Care Data Spaces – Adult Social Care Data Infrastructure, Centre for Care IMPACT Demonstrator scheme
· WM-ADASS — Development of a regional data space and analytics platform across 14 West Midlands Local Authorities to support evidence-based policy and social care market analysis.
Funding: ~£28,076 (2026-present)
-
HIP Collaborative Innovation Fund
, Royal Berkshire NHS Foundation Trust - Forecasting NHS staff retention using machine learning and large-scale workforce data.
Funding: £22,165. (2024-2025)
-
British Academy Funding
, University of Birmingham — Analysing the labour market consequences of dengue outbreaks using Brazilian
administrative data (RAIS and SINAN).
Funding: £5,000. (2023)
-
National Foundation for Science and Technology Development (NAFOSTED) —
Research on financial development, microfinance, and innovation among SMEs in Southeast Asia.
Funding: £5,000. (2016-2017)
Grants
and Awards
- Departmental PhD Scholarship, University of Birmingham (2021) — awarded +3 years of support.
- Development funds, University of Birmingham — supported advanced study at Oxford, Michigan State University, and LSE.
- Certificate of Distinction, University of Western Australia.
- Research Excellence Certificate, Vietnam Netherlands Program.
- Best Master’s Thesis (Distinction), Erasmus University Rotterdam — awarded €300.
- National Project (NAFOSTED), Ministry of Science and Technology, Vietnam — awarded £5,000.