Center for Global Development

The difference and system generalized method-of-moments estimators, developed by Holtz-Eakin, Newey, and Rosen (1988, Econometrica 56: 1371–1395); Arellano and Bond (1991, Review of Economic Studies 58: 277–297); Arellano and Bover (1995, Journal of Econometrics 68: 29–51); and Blundell and Bond (1998, Journal of Econometrics 87: 115–143), are increasingly popular. Both are general estimators designed for situations with “small T, large N″ panels, meaning few time periods and many individuals; independent variables that are not strictly exogenous, meaning they are correlated with past and possibly current realizations of the error; fixed effects; and heteroskedasticity and autocorrelation within individuals. This pedagogic article first introduces linear generalized method of moments. Then it describes how limited time span and potential for fixed effects and endogenous regressors drive the design of the estimators of interest, offering Stata-based examples along the way. Next it describes how to apply these estimators with xtabond2. It also explains how to perform the Arellano–Bond test for autocorrelation in a panel after other Stata commands, using abar. The article concludes with some tips for proper use.

Abstract The difference and system generalized method of moments (GMM) estimators are growing in popularity. As implemented in popular software, the estimators easily generate instruments that are numerous and, in system GMM, potentially suspect. A large instrument collection overfits endogenous variables even as it weakens the Hansen test of the instruments’ joint validity. This paper reviews the evidence on the effects of instrument proliferation, and describes and simulates simple ways to control it. It illustrates the dangers by replicating Forbes [ American Economic Review (2000) Vol. 90, pp. 869–887] on income inequality and Levine et al. [ Journal of Monetary Economics ] (2000) Vol. 46, pp. 31–77] on financial sector development. Results in both papers appear driven by previously undetected endogeneity.

* 1. The Case for Participation as Tyranny - Bill Cooke and Uma Kothari * 2. 'People's Knowledge', Participation and Patronage: Operations and Representations in Rural Development - David Mosse * 3. Institutions, Agency and the Limitations of Participatory Approaches to Development - Frances Cleaver * 4. Pluralism, Participation and Power: Joint Forest Management in India - Nicholas Hildyard, Pandurang Hegde, Paul Wolvekamp, Somasekhare Reddy * 5. Participatory Development at the World Bank: The Primacy of Process - Paul Francis * 6. Beyond the Formulaic: Process and Practice in South Asian NGOs - John Hailey * 7. The Social-Psychological Limits of Participation? - Bill Cooke * 8. Insights into Participation from Critical Management and Labour Process Perspectives - Harry Taylor * 9. Participatory Development: Power, Knowledge and Social Control - Uma Kothari * 10. Beyond Participation: Strategies for Deeper Empowerment - Giles Mohan * 11. Participation as Spiritual Duty: Empowerment as Secular Subjection - Heiko Henkel and Roderick Stirrat * Bibliography

BACKGROUND: Anemia is associated with an increased risk of cardiovascular and renal events among patients with type 2 diabetes and chronic kidney disease. Although darbepoetin alfa can effectively increase hemoglobin levels, its effect on clinical outcomes in these patients has not been adequately tested. METHODS: In this study involving 4038 patients with diabetes, chronic kidney disease, and anemia, we randomly assigned 2012 patients to darbepoetin alfa to achieve a hemoglobin level of approximately 13 g per deciliter and 2026 patients to placebo, with rescue darbepoetin alfa when the hemoglobin level was less than 9.0 g per deciliter. The primary end points were the composite outcomes of death or a cardiovascular event (nonfatal myocardial infarction, congestive heart failure, stroke, or hospitalization for myocardial ischemia) and of death or end-stage renal disease. RESULTS: Death or a cardiovascular event occurred in 632 patients assigned to darbepoetin alfa and 602 patients assigned to placebo (hazard ratio for darbepoetin alfa vs. placebo, 1.05; 95% confidence interval [CI], 0.94 to 1.17; P=0.41). Death or end-stage renal disease occurred in 652 patients assigned to darbepoetin alfa and 618 patients assigned to placebo (hazard ratio, 1.06; 95% CI, 0.95 to 1.19; P=0.29). Fatal or nonfatal stroke occurred in 101 patients assigned to darbepoetin alfa and 53 patients assigned to placebo (hazard ratio, 1.92; 95% CI, 1.38 to 2.68; P<0.001). Red-cell transfusions were administered to 297 patients assigned to darbepoetin alfa and 496 patients assigned to placebo (P<0.001). There was only a modest improvement in patient-reported fatigue in the darbepoetin alfa group as compared with the placebo group. CONCLUSIONS: The use of darbepoetin alfa in patients with diabetes, chronic kidney disease, and moderate anemia who were not undergoing dialysis did not reduce the risk of either of the two primary composite outcomes (either death or a cardiovascular event or death or a renal event) and was associated with an increased risk of stroke. For many persons involved in clinical decision making, this risk will outweigh the potential benefits. (ClinicalTrials.gov number, NCT00093015.)

Access to and use of mobile telephony in sub-Saharan Africa has increased dramatically over the past decade. Mobile telephony has brought new possibilities to the continent. Across urban–rural and rich–poor divides, mobile phones connect individuals to individuals, information, markets, and services. These effects can be particularly dramatic in rural Africa, where in many places mobile phones have represented the first modern telecommunications infrastructure of any kind. Mobile phones have greatly reduced communication costs, thereby allowing individuals and firms to send and to obtain information quickly and cheaply on a variety of economic, social, and political topics. An emerging body of research shows that the reduction in communication costs associated with mobile phones has tangible economic benefits, improving agricultural and labor market efficiency and producer and consumer welfare in specific circumstances and countries. This paper first examines the evolution of mobile phone coverage and adoption in sub-Saharan Africa over the past decade. We then explore the main channels through which mobile phones can effect economic outcomes and appraise current evidence of its potential to improve economic development. We conclude with directions for future research and outline the necessary conditions for mobile phones to promote broader economic development in Africa.

At the heart of many econometric models are a linear function and a normal error. Examples include the classical small-sample linear regression model and the probit, ordered probit, multinomial probit, tobit, interval regression, and truncated-distribution regression models. Because the normal distribution has a natural multidimensional generalization, such models can be combined into mul-tiequation systems in which the errors share a multivariate normal distribution. The literature has historically focused on multistage procedures for fitting mixed models, which are more efficient computationally, if less so statistically, than maximum likelihood. Direct maximum likelihood estimation has been made more practical by faster computers and simulated likelihood methods for estimating higher-dimensional cumulative normal distributions. Such simulated likelihood methods include the Geweke–Hajivassiliou-Keane algorithm (Geweke, 1989, Econometrica 57: 1317–1339; Hajivassiliou and McFadden, 1998, Econometrica 66: 863–896; Keane, 1994, Econometrica 62: 95–116). Maximum likelihood also facilitates a generalization to switching, selection, and other models in which the number and types of equations vary by observation. The Stata command cmp fits seemingly unrelated regressions models of this broad family. Its estimator is also consistent for recursive systems in which all endogenous variables appear on the right-hand sides as observed. If all the equations are structural, then estimation is full-information maximum likelihood. If only the final stage or stages are structural, then estimation is limited-information maximum likelihood. cmp can mimic a score of built-in and user-written Stata commands. It is also appropriate for a panoply of models that previously were hard to estimate. Heteroskedasticity, however, can render cmp inconsistent. This article explains the theory and implementation of cmp and of a related Mata function, ghk2(), that implements the Geweke–Hajivassiliou–Keane algorithm.

This article presents evidence that-alongside the successes-many information systems in developing countries can be categorized as failing either totally or partially. It then develops a new model that seeks to explain the high rates of failure. The model draws on contingency theory in order to advance the notion of design-actuality gaps: the match or mismatch between IS designs and local user actuality. This helps identify two high-risk archetypes that affect IS in developing countries: country context gaps and hard-soft gaps. The model is also of value in explaining the constraints that exist to local IS improvisations in developing countries. Overall, the article shows how model and theory help understand IS cases in developing countries, and equally, how those cases provide valuable data to help develop IS models and theories.

Some natural resources-oil and minerals in particular-exert a negative and nonlinear impact on growth via their deleterious impact on institutional quality. We show this result to be very robust. The Nigerian experience provides telling confirmation of this aspect of natural resources. Waste and corruption from oil rather than Dutch disease has been responsible for its poor long run economic performance. We propose a solution for addressing this resource curse which involves directly distributing the oil revenues to the public. Even with all the difficulties of corruption and inefficiency that will no doubt plague its actual implementation, our proposal will, at the least, be vastly superior to the status quo. At best, however, it could fundamentally improve the quality of public institutions and, as a result, transform economics and politics in Nigeria.

The widely publicized finding that “aid promotes growth in a good policy environment” is not robust to the inclusion of new data or alternative definitions of “aid,” “policy” or “growth.” The idea that “aid buys growth” is on shaky ground theoretically and empirically. It doesn’t help that aid agencies face poor incentives to deliver results and underinvest in enforcing aid conditions and performing scientific evaluations. Aid should set more modest goals, like helping some of the people some of the time, rather than trying to be the catalyst for societywide transformation.

Participation is a popular approach to project implementation, policy-making and governance in both developing and developed countries. Recently, however, it has become fashionable to dismiss participation as more rhetoric than substance, and subject to manipulation by those intent on pursuing their own agendas under cover of community consent. This books seeks to rebut this simplistic conclusion. It describes and analyses new experiments in participation from a wide range of situations that show how, far from being a redundant and depoliticizing concept, participation can be linked to genuinely transformative processes and outcomes - provided that a political and not a technocratic approach is taken. It examines the recent convergence between participatory development and participatory governance, and the role of all the main actors - the state, civil society and donor agencies. It takes contemporary advances in development theory into account and proposes theoretical and practical ways forward.

BACKGROUND: occurs in 3 to 4% of patients with non-small-cell lung cancer (NSCLC). We evaluated the efficacy and safety of tepotinib, a highly selective MET inhibitor, in this patient population. METHODS: exon 14 skipping mutation was detected on liquid biopsy or tissue biopsy. RESULTS: As of January 1, 2020, a total of 152 patients had received tepotinib, and 99 patients had been followed for at least 9 months. The response rate by independent review was 46% (95% confidence interval [CI], 36 to 57), with a median duration of response of 11.1 months (95% CI, 7.2 to could not be estimated) in the combined-biopsy group. The response rate was 48% (95% CI, 36 to 61) among 66 patients in the liquid-biopsy group and 50% (95% CI, 37 to 63) among 60 patients in the tissue-biopsy group; 27 patients had positive results according to both methods. The investigator-assessed response rate was 56% (95% CI, 45 to 66) and was similar regardless of the previous therapy received for advanced or metastatic disease. Adverse events of grade 3 or higher that were considered by investigators to be related to tepotinib therapy were reported in 28% of the patients, including peripheral edema in 7%. Adverse events led to permanent discontinuation of tepotinib in 11% of the patients. A molecular response, as measured in circulating free DNA, was observed in 67% of the patients with matched liquid-biopsy samples at baseline and during treatment. CONCLUSIONS: exon 14 skipping mutation, the use of tepotinib was associated with a partial response in approximately half the patients. Peripheral edema was the main toxic effect of grade 3 or higher. (Funded by Merck [Darmstadt, Germany]; VISION ClinicalTrials.gov number, NCT02864992.).

Executive Overview Global leadership has been identified as a critical success factor for large multinational corporations. While there is much writing on the topic, most seems to be either general advice (i.e., being open minded and respectful of other cultures) or very specific information about a particular country based on a limited case study (do not show the soles of your shoes when seated as a guest in an Arab country). Both kinds of information are certainly useful, but limited from both theoretical and practical viewpoints on how to lead in a foreign country. In this paper, findings from the Global Leadership and Organizational Behavior Effectiveness (GLOBE) research program are used to provide a sound basis for conceptualizing worldwide leadership differences. We use a hypothetical case of an American executive in charge of four similar teams in Brazil, France, Egypt, and China to discuss cultural implications for the American executive. Using the hypothetical case involving five different countries allows us to provide in-depth action oriented and context specific advice, congruent with GLOBE findings, for effectively interacting with employees from different cultures. We end the paper with a discussion of the challenges facing global executives and how corporations can develop useful global leadership capabilities.

Abstract There is consensus that the global food system is not delivering good nutrition for all and is causing environmental degradation and loss of biodiversity, such that a profound transformation is needed to meet the challenges of persistent malnutrition and rural poverty, aggravated by the growing consequences of climate change. Agroecological approaches have gained prominence in scientific, agricultural and political discourse in recent years, suggesting pathways to transform agricultural and food systems that address these issues. Here we present an extensive literature review of concepts, definitions and principles of agroecology, and their historical evolution, considering the three manifestations of agroecology as a science, a set of practices and a social movement; and relate them to the recent dialogue establishing a set of ten iconic elements of agroecology that have emerged from a global multi-stakeholder consultation and synthesis process. Based on this, a consolidated list of principles is developed and discussed in the context of presenting transition pathways to more sustainable food systems. The major outcomes of this paper are as follows. (1) Definition of 13 consolidated agroecological principles: recycling; input reduction; soil health; animal health; biodiversity; synergy; economic diversification; co-creation of knowledge; social values and diets; fairness; connectivity; land and natural resource governance; participation. (2) Confirmation that these principles are well aligned and complementary to the 10 elements of agroecology developed by FAO but articulate requirements of soil and animal health more explicitly and distinguish between biodiversity and economic diversification. (3) Clarification that application of these generic principles can generate diverse pathways for incremental and transformational change towards more sustainable farming and food systems. (4) Identification of four key entry points associated with the elements: diversity; circular and solidarity economy; co-creation and sharing of knowledge; and, responsible governance to enable plausible pathways of transformative change towards sustainable agriculture and food systems.

Abstract Soils store more carbon than other terrestrial ecosystems 1,2 . How soil organic carbon (SOC) forms and persists remains uncertain 1,3 , which makes it challenging to understand how it will respond to climatic change 3,4 . It has been suggested that soil microorganisms play an important role in SOC formation, preservation and loss 5–7 . Although microorganisms affect the accumulation and loss of soil organic matter through many pathways 4,6,8–11 , microbial carbon use efficiency (CUE) is an integrative metric that can capture the balance of these processes 12,13 . Although CUE has the potential to act as a predictor of variation in SOC storage, the role of CUE in SOC persistence remains unresolved 7,14,15 . Here we examine the relationship between CUE and the preservation of SOC, and interactions with climate, vegetation and edaphic properties, using a combination of global-scale datasets, a microbial-process explicit model, data assimilation, deep learning and meta-analysis. We find that CUE is at least four times as important as other evaluated factors, such as carbon input, decomposition or vertical transport, in determining SOC storage and its spatial variation across the globe. In addition, CUE shows a positive correlation with SOC content. Our findings point to microbial CUE as a major determinant of global SOC storage. Understanding the microbial processes underlying CUE and their environmental dependence may help the prediction of SOC feedback to a changing climate.

Price dispersion across markets is common in developing countries. Using novel market and trader-level data, this paper provides estimates of the impact of mobile phones on price dispersion across grain markets in Niger. The introduction of mobile phone service between 2001 and 2006 explains a 10 to 16 percent reduction in grain price dispersion. The effect is stronger for market pairs with higher transport costs. (JEL O13, O33, Q11, Q13)

This paper analyses the parties and party systems that have begun to emerge in sub-Saharan Africa's fledgling multiparty systems. Using a data base of 87 legislative elections convened in the 1990s, the paper identifies three trends. The position of parties late in the decade is primarily tributary of their performance in the first multiparty election conducted in the early 1990s. Parties that won founding elections are almost invariably still in power. Secondly, the typical emerging party system has consisted of a dominant party surrounded by a large number of small, unstable parties. Thirdly, party cleavages have been overwhelmingly ethno-linguistic in nature, while ideological and programmatic debates have been muted and rare. The second half of the paper provides tentative explanations for these striking patterns. It emphasises the illiberal nature of most of the new African democracies, their characteristic centralisation of power around the presidency, and the pervasive clientelism that structures the relationship between the state and the citizenry. These characteristics shape the incentives faced by individual politicians and thus much of their behaviour.

Sexual and reproductive health and rights (SRHR) are fundamental to people's health and survival, to economic development, and to the wellbeing of humanity. Several decades of research have shown—and continue to show—the profound and measurable benefits of investment in sexual and reproductive health. Through international agreements, governments have committed to such investment. Yet progress has been stymied because of weak political commitment, inadequate resources, persistent discrimination against women and girls, and an unwillingness to address issues related to sexuality openly and comprehensively. Health and development initiatives, including the 2030 Agenda for Sustainable Development and the movement toward universal health coverage, typically focus on particular components of SRHR: contraception, maternal and newborn health, and HIV/AIDS. Countries around the world have made remarkable gains in these areas over the past few decades, but the gains have been inequitable among and within countries, and services have often fallen short in coverage and quality. Moreover, in much of the world, people have insufficient access to a full set of sexual and reproductive health services, and their sexual and reproductive rights are not respected or protected. Acceleration of progress therefore requires adoption of a more holistic view of SRHR and tackling of neglected issues, such as adolescent sexuality, gender-based violence, abortion, and diversity in sexual orientations and gender identities.

Introduction: Mkomazi - HISTORIES The history of the plains - 'We just left it': contest over the plains up to 1953 - The history of the reserve - ENVIRONMENTS Environmental degradation - Biodiversity - PEOPLE Livelihoods - Regional conequences - Benefits & resistance - A desert strange

Recent research yields widely divergent estimates of the cross-country relationship between foreign aid receipts and economic growth. We propose and test two reasons for this divergence, both of which relate to the timing of effects between aid and growth. First, these studies have insufficiently considered the lag with which aid might affect growth, particularly certain kinds of aid. Second, they have sought to reduce the bias from contemporaneous reverse causation with the use of instrumental variables that appear to be invalid, weak, or both. We reanalyze data from the three most influential published aid-growth studies, strictly conserving their regression specifications, adding sensible assumptions about timing and avoiding questionable instruments. With these changes, the research designs from all of these studies yield one finding: that increases in aid have been followed on average by modest increases in investment and growth. The most plausible explanation is that aid causes some degree of growth in recipient countries, though the magnitude of this relationship is modest, varies greatly across recipients, and diminishes at high levels of aid.

Duffy (