5.2.2 Approaches to costing

Several approaches can be used to construct a cost basis (costing) for a strategy or programme. They all relate an input of costs allocated to certain activities to some output in connection with strategies/targets, and ultimately results (outcomes). Different costing approaches have different strengths and weaknesses and uses, and several are often used in combination. They are described here, and summarized in Table 5.1:

Incremental budgeting approach (IBA)

Perhaps the most common approach in use. It provides a contrast to the FNA’s focus on “costing” rather than budgeting since budgets are constrained by available funding, whereas the costing in the FNA should indicate realistic needs independent of available budgets. In incremental budgeting, the previous year’s budget is taken as a starting point and a percentage increase (or decrease) is applied. This approach is not recommended because it does not adequately address the basic principles outlined above.

Historical projections

Historical costs are used to project future costs. This could differ from incremental budgeting if it builds on detailed historical activity or results-based costs. Where detailed historical costs are known, these can be used to estimate future costs for specific activities. For example, the costs for replanting a hectare of mangroves in the past can be used to estimate the costs of replanting a targeted amount in a specific country or area in future. When using historical costs, it is important to: 1) make sure they are accurate and cover the entire cost of an activity; 2) base the new costs on specific biodiversity management targets (i.e. number of hectares, days of ranger missions); and 3) account for inflation, diminishing marginal returns, economies of scale and any other issues that would affect future costs.

Cost modelling

Estimating future costs based on quantitative models with input variables. Models are almost always used for costing and can be as simple as multiplying a unit cost by the number of units needed. However, this approach here generally refers to complex, potentially non-linear, models with multiple variables. For example, models for estimating protected areas costs based on their area, distance from cities and local purchasing price parity, have been derived from historical costs and used to make future costing predictions. Complex models supported by the literature may be useful for the FNA, especially in cases where actions are new to a country with no available historical estimates.

Activity-Based costing (ABC)

Estimating budgets based on specific programmes and activities identified and the costs related to those activities. Administrative overheads are tied to activities more closely than in traditional budgeting (which simply adds on administrative costs as a supplement). This is useful when details of biodiversity activities are well known (and quantified), tracking project or programme “outputs” (immediate results of actions) is desired and the “outcomes” (longer-term results) of activities are difficult to quantify or track. For this approach, it is useful to have a catalogue of costing units to help cost activities in an integrated manner.

Results-Based costing (RBC)

An expansion of activity-based costing where all costs are associated with specific medium- to long-term results, so that the “outcome” of the activity is the budgeting focus and not the activity or short-term outputs. There is a strong push towards this type of costing in national budgeting processes. It is also called “performance-based budgeting,” because it allows the finance ministry and central planning agencies to more easily track performance. RBC is described in further detail below. This approach could also be framed as a finance solution to improve efficiency and cost-effectiveness in biodiversity spending.

Box 5.2: Moving from Incremental to Results-Based Budgeting - Peru


Peru’s “National Budget System Reform Strategy”5 promotes the use of results-based budgeting (RBB) to ensure the government provides people with the planned quantity and quality of goods and services. The RBB strategy demands:

  • Clear and objective definitions of the results to be achieved;

  • Commitment by government entities to achieve these results;

  • Clear responsibilities in implementing instruments and accountability of public expenditure; and

  • Mechanisms to generate information on products, results and management efforts.

This strategy is implemented by the Ministry of Economy and Finance through: i) budget programmes, ii) performance monitoring based on indicators, iii) independent evaluations, and iv) management incentives.

Table 5.1: Summary of the Costing Approaches

Costing Approach Common Use Opportunities Challenges
Incremental Budgeting Approach Annual increments allocated, most budgets Gradual change Limited vision, lack of connection with results
Historical Projections Empirical data used for budgeting Accurate, based on real experience Not comprehensive, may not be optimal but based on limited budgets
Cost Modelling Extrapolation from small cases, budgeting new activities Alternative scenarios, understanding cost effectiveness Lack of empirical data, country or geographic specificity
Activity-Based Costing Project budgeting, programme budgets Detailed bottom-up budgeting Not necessarily focused on outcomes
Results-Based Costing Planning by objectives, log frame, programme- based budgeting Best practice, detailed, focused on outcomes Advanced approach, not used in most countries

BIOFIN encourages building up budgets from smaller costable actions and budget line items. Using a catalogue of unit costs is also useful in order to base activity cost estimations in welldefined categories such as human resources, infrastructure, equipment, inputs, consultancies and public consultations, among others. In future, it may be possible to build refined models for future biodiversity management budgeting needs, based on data from a wide range of BIOFIN countries and biodiversity activities linked to strategies and results, similar to models currently used in health care and education. In all cases, unit costs should be based on government norms, research and published documents, and be peer reviewed or validated. Economics and biodiversity literature provides some useful cost estimates for particular actions such as reforestation costs, coral reef restoration, and seagrass restoration. (See Box 5.3).

Box 5.3:s Cost Modelling to Estimate Biodiversity Management Costs - Thailand

Cost models can derive cost estimates for defined actions. They can help introduce comparable unit costs for different actions that may be chosen to achieve the same objective. The options for coral reef restoration and coastal erosion prevention have been estimated by Thailand using a modelling tool that may be adapted to other countries. Note that the cheapest actions are not necessarily the most efficient or cost-effective.

Coral Reef Restoration Costs

Restoration Methods Unit Cost (Baht/Rai) Unit Cost (Baht/Ha)
Transplanting on concrete 106,400 17,024
Providing Artificial Reef 7,560,000 1,209,600
Floating Nursery 18,720,800 2,995,328

Source. N. Thongtham. Unpublished Report. Department of Marine and Coastal Resources, Thailand.

Coastal Erosion Prevention

Protection Measures Unit Cost (Baht/Meter) Durability and Effectiveness*
1. Geo-bag/Geo-tube/Geo-container 9,300 ++
2. Bamboo Wall 3,850 +
3. Concrete Sea Wall 31,600 +++
4. Revetment 13,300 +++
5. Offshore Breakwater 200,000 +++
6. Sand Sausage 30,000 ++
7. Groin (Groyne) 70,000 ++
8. Gabion Box 18,000 +

* Note: Effectiveness depends to a large extent on the physical terrain of the site; different protection measures are suitable for different physical conditions.

BIOFIN recommends RBC, or elements from it, in line with best practice in public budgeting. Working backwards from impacts to outcomes, outputs, and actions is a common planning approach and is part of a logical framework methodology. Many countries are moving toward RBC to ensure good governance and hold different government agencies to high standards. Early adoption of RBC-RBB reforms in the ministry of environment can help to achieve cost-effectiveness, and also qualify priority institutions for additional allocations. The extent to which results-based costing is adopted or appropriate for the FNA will depend on each country’s capacity and appetite, particularly in the finance ministry