Measuring impacts of conservation interventions on human wellbeing and the environment in northern Cambodia

Publication Details

3ie Funded Evaluation, DPW1.1045. A link to the completed study will appear here when available.

Tom Clements, Malyne Neang, E.J. Milner-Gulland, Seng Suon
Institutional affiliations
None specified
Grant-holding institution
None specified
East Asia and Pacific (includes South East Asia)
Environment and Disaster Management
None specified
Gender analysis
None specified
Gender analysis
Equity Focus
None specified
Evaluation design
Difference-in Difference (DID), Propensity Score Matching (PSM), Randomised Control Trials (RCT)
Ongoing 3ie Funded Studies
3ie Funding Window
Development Priorities Window 1


This study investigates the environmental and social outcomes of protected areas (PAs) and payment for ecosystem service (PES) programmes in Cambodia.


There is now widespread acceptance that environmental conservation policies should, at the very least, do no harm, and where possible should contribute to poverty alleviation (Convention on Biological Diversity, 2008). As far as social outcomes are concerned, there is relatively little evidence about whether conservation interventions work, why they work, and under what circumstances. Most published studies to date have focused on assessing environmental rather than social outcomes, for example, using impact evaluation methods to show that PAs and PES policies do indeed protect forests (e.g. Andam et al. 2008). This study will have relevance to the debate around the costs and benefits of environmental conservation nationally in Cambodia, in Southeast Asia and globally.

Research questions

  1. Do PAs and PES protect forests in comparison with control groups?
  2. Do PAs have positive or negative impacts on human wellbeing?
  3. Do PES programmes deliver additional benefits to human wellbeing in comparison with control groups?
  4. Do the different environmental conservation programmes have different impacts on different livelihood strategies, focusing on rice farmers, growers of cash crops and non-timber forest product collectors?
  5. Do households reduce land-clearing behaviour as a result of the payment programmes?


Intervention design

This evaluation focuses on two mainstream environmental conservation policies: establishment of PAs and PES in northern Cambodia. The PAs were established first, in 2005, and included 16 resident villages. From 2008, three PES programmes were rolled out to complement the PA management: 1) direct payments to households for species protection; 2) community-managed ecotourism linked to wildlife and habitat protection; and 3) payments to households to keep within land use boundaries

Theory of change

The causal pathway assumes that through capacity building and support it is possible to establish functional PA management authorities that have the capacity, interest and sufficient political support to undertake patrolling and law enforcement actions. If successful, law enforcement coverage will be adequate, perpetrators will be detected and successfully prosecuted, and law enforcement will act as an effective deterrent to hunting and further encroachment. As a consequence, deforestation rates should decline and populations of wildlife species should increase. The PES programme builds upon a foundation of agreed village land-use and natural resource management plans.

Critical assumptions include that villages are interested to receive secure land titles and resource management rights in exchange for constraints on behaviour, and that village authorities administer the programmes in a manner that is acceptable to the local population. Generating peer pressure, in terms of social pressure within the village to comply, is an important aspect of the theory of change.

Evaluation design

This impact evaluation will quantify the impact of PAs and PES on environmental and human wellbeing outcomes for a panel of intervention and matched control villages and households. Matching methods will be used to select villages and households within villages to form an appropriate comparison group. Panel methods will then be used to follow trends in environmental and social outcome measures for the same villages and households over time, using before after data where it exists. Combining matching and difference-in-difference methods helps to control for both observable and unobservable sources of bias ensuring that valid comparisons are made. The environmental assessment will investigate deforestation rates around within-PA villages compared to matched controls, and comparing villages inside PAs with PES programmes to those without. The social assessment will investigate household poverty status, measured using the Basic Necessities Survey (BNS), for households from within-PA villages compared to matched controls, and for households that benefited from the PES programmes compared to matched controls. In addition, an RCT will be conducted for the Ibis Rice PES over a four-year period of planned expansion (2016-2019), to evaluate the extent of its impact on human behaviours such as unapproved clearance of forest, commercial hunting, and logging.

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