In agricultural
extension, we often ask, “Did the program work?”
But the smarter question is, “How did it work and through what pathways?”
That’s where the Imai–Tingley
Framework for Causal Mediation Analysis comes in. Developed by Kosuke
Imai, Luke Keele, and Dustin Tingley, it helps researchers uncover why
and how interventions influence farmers’ behavior and outcomes.
What It Does?
Traditional regression
shows whether an intervention affects an outcome. The Imai–Tingley
framework goes further by dividing the total effect into:
Indirect
effect (ACME): the part explained by a mediator (like knowledge, trust, or
empowerment)
Direct
effect (ADE): the remaining influence not through that mediator
It’s grounded in the
potential outcomes framework, handles nonlinear models, and is implemented in R using the mediation package.
Why It Matters in
Agricultural Extension
Extension programs
rarely change outcomes directly. They work through social, psychological, and
institutional mechanisms, changing farmers’ knowledge, confidence, or networks.
This framework helps researchers measure those invisible channels of change.
It turns impact
evaluation into mechanism evaluation.
Real-World Examples
- Training
and Knowledge: Does climate-smart agriculture training increase adoption
through improved knowledge?
- Peer
Networks: Do farmers adopt new seeds because of extension agents — or
because of peer discussions?
- Gender
Empowerment: Do women-focused programs improve food security through
empowerment?
- Digital
Trust: Does mobile advisory adoption depend on trust in digital
information?
- Institutional
Pathways: Do FPO policies raise income through better market access?
Each case identifies how
change happens, not just if it happens.
Blending Numbers with
Narratives
Quantitative mediation
estimates the “how much.” Qualitative insights
explain the “why.”Together, they build
stronger, evidence-based stories of agricultural transformation.
The Imai-Tingley Framework helps agricultural researchers move away from asking, “Did it work?”
to “How and for whom did it work?” By revealing the
pathways of change, knowledge, trust, empowerment, networks, it guides smarter
design of future extension programs.
The Imai-Tingley
framework vs the Structural Equation Modeling
🔹 SEM Path Analysis
- Focuses
on associations between variables.
- Explains
how variables are statistically related (direct and indirect
effects).
- Commonly
used for theoretical model testing (e.g., SmartPLS, AMOS).
- Interpretation:
“Farmers who use digital extension tend to adopt more practices, and
adoption is linked to higher yield.”
Associational, not
strictly causal.
🔹 Imai–Tingley Causal Mediation
- Focuses
on causal mechanisms.
- Decomposes
the total effect of a treatment into:
Direct effect: digital extension → yield (not
through adoption)
Indirect effect: digital extension → adoption →
yield
- Uses
counterfactual (what-if) logic to estimate how much of the yield change
is caused by adoption.
The relationship is causal, not just
correlational.
The main difference between SEM path analysis and the Imai–Tingley causal mediation framework is their analytical focus. Path analysis examines the statistical associations between variables to test theoretical relationships, demonstrating how constructs such as digital extension use, adoption of improved practices, and yield are interconnected. However, it does not confirm causality. In contrast, the Imai–Tingley framework
uses a counterfactual, causal inference approach to decompose the total effect
of an intervention into direct and indirect (mediated) effects. It determines
how much of the yield improvement is caused by adoption behavior, making
it more suitable for identifying causal mechanisms.
* Dr. Paul Mansingh, J
*Professor & Head, Department of Agricultural Extension & Economics,
VIT School of Agricultural Innovations and Advanced Learning (VAIAL),
Vellore Institute of Technology, Vellore 632014
Mr. Atsu Frank Yayra Ihou
Teaching Cum Research Assistant,
Department of Agricultural Extension & Economics,
VIT School of Agricultural Innovations and Advanced Learning (VAIAL),
Vellore Institute of Technology, Vellore 632014