Use of the terms efficiency versus effective in conservation

Conservation professionals must consider that resources are scarce, human capacities are limited, and the results of conservation actions must be maximized. Decision-makers in conservation are responsible for prioritizing investments to obtain the most conservation profit. As with emergency medicine, prioritizing actions in conservation is called triage (Bottrill et al., 2008; Gerber, 2016; Hayward & Castley, 2018). Strategies and plans for biodiversity management aim to find solutions that require the minimum amount of effort to optimize the cost-effectiveness of investments (Adams, 2024; Ando et al., 1998; Pienkowski et al., 2021). In other words, conservation management seeks the most efficient measures. The design of efficient conservation plans is expected to improve economic support, maximize the output of conservation investment, and help conserve species by increasing the availability of resources. However, the quantification of associated economic resources has received little attention in conservation, and analyses of the efficiency of management measures are limited (White et al., 2022).

Understanding the context in which the term efficiency is used in biodiversity conservation is crucial. This term is commonly employed in scientific literature, and its interpretation and use vary. Researchers may discuss the efficiency of resource allocation in conservation (Laycock et al., 2009; Wilson et al., 2007). This can involve evaluating how well financial resources, the workforce, or technology are used to achieve conservation goals. Efficiency may be assessed in terms of the performance of different conservation strategies. For example, researchers might compare the efficiency of protected areas versus community-based conservation approaches (Brodie et al., 2015). The term might be applied in evaluations of the efficiency of policies in promoting biodiversity conservation (Cummings et al., 2018). This could include assessing the impact of regulations, incentives, or penalties on conservation outcomes. Efficiency may also be considered in the context of ecosystem services (Cao et al., 2019). For example, managers may seek conservation measures that efficiently protect and enhance ecosystem services, such as pollination, water purification, and carbon sequestration. In scientific research, efficiency may refer to the cost-effectiveness of data collection and monitoring methods (Joseph et al., 2006). Researchers may explore how efficiently data are gathered to assess biodiversity status and the success of conservation interventions. The need for efficient conservation measures is a pressing concern that should motivate work that makes a meaningful difference in biodiversity conservation.

Whatever the case, improving management efficiency should have measurable positive effects on biodiversity conservation. Consequently, conservation actions should be prioritized such that cost and effectiveness are balanced (Lindsey et al., 2005; Pienkowski et al., 2021; White et al., 2022). In other words, they should be not only effective, but also efficient. Efficiency refers to the ability to achieve a desired outcome with minimal waste or effort, whereas effectiveness refers to the ability to produce the desired result. For example, the use of an atomic bomb to exterminate a mosquito population is effective but not efficient. Whereas this linguistic difference is evident in the previous example, the terminology is sometimes misused; Merriam-Webster Dictionary includes in the definition of efficient a comparison among efficient, effective, and proficient because “these three words cover some overlapping territory” (Merriam-Webster, 2024).

The confusion may be more pronounced regarding conservation actions because efficiency is often mistakenly used in academic or public discussions when effectiveness is meant. Although these terms are distinguishable relative to conservation (Laycock et al., 2009), conservation managers and researchers use them indiscriminately and interchangeably (Wilson et al., 2007).

Concern about cost-effectiveness has increased notably, and much recent conservation research focuses on it (Pienkowski et al., 2021). However, in general, approaches for identifying priorities for conservation neglect costs and provide static assessments, although recent theoretical studies incorporate economic considerations (White et al., 2022; Wilson et al., 2007). Researchers and practitioners discuss efficiency in conservation actions, but the term efficiency is sometimes used carelessly. We examined how researchers in the scientific literature are using efficiency.

We reviewed how authors of articles published in Conservation Biology, one of the most prestigious journals on the subject, used efficiency. We searched Web of Science for Conservation Biology articles published from 1987 to September 2024 in which the term efficiency and its variants (efficien*) were used. We searched all article fields (e.g., title, abstract). From the articles discovered in the search, we checked the usage of the term efficiency manually. We noted correct or incorrect usage and the conservation actions considered in each article. Our conservation actions we noted were based on those listed in Salafsky et al. (2008). We determined whether the study included efficiency evidence (surveys, interviews, documents, or field data) and how efficiency was measured. For articles that contained the word cost, we determined whether a numeric value of this cost was provided. Finally, we noted the name of the taxa targeted, the study location, and the country or geographic territory when possible.

We found 256 articles that contained the term efficiency or its variants (Appendix S1). According to the definition of efficiency (see above), the word was used correctly in 143 publications and incorrectly in 50. In 41 studies, the term's use was unrelated to conservation action. We could not assess usage in 22 publications, mainly because the word was not used enough times to confirm the definition (Figure 1). The most mentioned conservation actions considered in our analyzed studies were research and conservation planning actions, followed by area protection and species and area management actions, regardless of whether authors correctly or incorrectly used the term efficiency (Figure 1).

In 143 of 256 articles (55.9%), authors used efficiency correctly. However, they did not clarify why the conservation action, the research, or the method were efficient, suggesting that a specific measure is efficient without clarification about why. Of the 143 papers in which the term was used correctly, only 17 offered evidence of efficiency (with fieldwork or surveys) (Figure 1).

According to Zidane and Olsson (2017), efficiency is related to doing things in a less wasteful manner, but they also say, correctly, that it is related to doing things in a way that makes things effective. Therefore, efficiency is often used simply to attract readers. Two hundred thirty-five of 256 the reviewed articles (92%) included had efficiency in the abstract. Of these 235, 33 articles included the term efficiency only once in the abstract. Twenty articles contained 2 mentions, one in the abstract and the other in the text, generally in the introduction or the last paragraph of the discussion in dogmatic concluding sentences. In these cases, efficiency was used to attract reader attention and had no real meaning. The usage may be correct, but it is relatively meaningless.

In 50 reviewed articles, the concept of efficiency was misused. In 46 (92%) of these, efficiency was misused because its meaning was confused with the meaning of effectiveness. These concepts are related, but they refer to different aspects of performance and outcomes of an action. Whereas efficiency emphasizes optimizing processes and resource use, effectiveness focuses on accomplishing objectives and the overall impact of activities, and this latter factor is what the authors referred to. An efficient system or process aims to produce maximum output with minimum input. In many cases, authors defined as efficient some conservation actions that were effective but not efficient. In this context, there were 22 publications in which readers would not have been able to assess whether efficiency was used correctly because of a lack of clarity in the authors’ use of effectiveness and efficiency. In articles where efficiency was used correctly, only 17 (6.3%) provided evidence of efficiency, 6 of them with surveys (e.g., measuring and selecting the least-cost corridors for species or comparing the efficiency of rare species capture) and the remaining 10 with field measures or estimations (e.g., measuring the cost-effectiveness ratio of conservation actions).

The term cost was used in 60% of papers (155), but only 23% (59 out of 256) included a numeric value for cost of the conservation action. White et al. (2022) found in similar research that only 13.3% of reviewed studies provided quantitative costs (n = 1987 studies). The reference to financial costs and their measurement are rare in conservation plan implementation (Iacona et al., 2018; Lindsey et al., 2005) because these costs are difficult to measure generally (White et al., 2022). However, the inclusion, compilation, and reporting of economic cost data should be mandatory in conservation plans and actions, with the aim of improving conservation decision-making (Adams, 2024; Iacona et al., 2018; White et al., 2022). The identification of financial priorities for the purpose of assigning resources should also be part of strategic plans and conservation actions (Balmford et al., 2000; Gerber, 2016; Pienkowski et al., 2021).

Confusion may arise when people use efficiency and effectiveness interchangeably or when one (mainly efficiency) is prioritized over the other without considering the overall impact of this use. It is essential for researchers to recognize the distinctions between efficiency and effectiveness and to strike a balance that aligns with their goals and values. Sometimes, the reason researchers use efficiency instead of effectiveness is easily seen: efficiency is an attractive word and more suggestive than effectiveness. Sometimes, there is no actual awareness of the difference between these terms.

According to Merriam-Webster Dictionary (2024), efficiency focuses on “how little is wasted or lost while the desired results are produced.” This focus is absolutely critical in conservation plans and strategies (Adams, 2024; Gerber, 2016; Pienkowski et al., 2021). The term efficiency should be clearly defined within the specific context of the research to avoid confusion with the word effectiveness and to ensure a shared understanding among scientists and practitioners. Conservation researchers, planners, and practitioners, who attend to the precarious status of biodiversity, need to distinguish between these terms clearly.