Recall biases in retrospective survey data are widely considered to be pervasive and have important implications for effective agricultural research. In this paper, we leverage the survey design literature and test three strategies to attenuate mental anchoring in retrospective data collection: question order effects, retrieval cues, and aggregate (community) anchoring. We embed a survey design experiment in a longitudinal survey of smallholder farmers in Malawi and focus on anchoring bias in maize production and happiness exploiting differences between recalled and concurrent responses. We find that asking for retrospective data before concurrent data reduces recall bias by approximately 34% for maize production, a meaningful improvement with no increase in survey data collection costs. Retrieval cues are less successful in reducing the bias for maize reports and involve more data collection time, while community anchors can exacerbate the bias. Reversing the order of questions and retrieval cues do not help to ease the bias for happiness reports.

Understanding the magnitude and source of measurement biases in self-reported data is critical to effective economic policy research. This paper examines the role of anchoring bias in self-reports of objective and subjective outcomes under recall. The research exploits a unique panel survey data set collected over a three-year period from four countries in Central America. It assesses whether respondents use their reported value of specific measures from the most recent survey period as a cognitive heuristic when recalling the value from a previous period, while controlling for the value they reported earlier. We find strong evidence of sizable anchoring bias in self-reported retrospective indicators for both objective measures (household and per capita income, wages, and hours spent on the household’s main activity) and subjective measures (reports of happiness, health, stress, and well-being). In general, we also observe a larger bias in response to negative changes for objective indicators and a larger bias in response to positive changes for subjective indicators.

These Guidelines represent the first attempt to provide international recommendations on collecting, publishing, and analysing subjective well-being data.

Coffee is a growth market. Current estimates indicate that global coffee production (in volume) has increased by more than 60% since the 1990s. Coffee is produced by around 25 million farmers, which are mainly smallholders in developing and least developed countries, and over 70% of the coffee produced is exported, resulting in about 20 billion US dollars annual foreign exchange earnings (ICO, 2020). COVID-19 represented a severe joint supply and demand shock to the global coffee sector, particularly during the first months after the start of the pandemic. As noted by Hernandez et al. (2020), the coffee industry experienced important disruptions downstream the value chain, including the functioning of key export infrastructure and international shipping, which combined with local currency devaluations and volatile coffee prices, which resulted in significant challenges for coffee growers, farm workers, and traders.

This open access book demonstrates how data quality issues affect all surveys and proposes methods that can be utilised to deal with the observable components of survey error in a statistically sound manner. This book begins by profiling the post-Apartheid period in South Africa's history when the sampling frame and survey methodology for household surveys was undergoing periodic changes due to the changing geopolitical landscape in the country. This book profiles how different components of error had disproportionate magnitudes in different survey years, including coverage error, sampling error, nonresponse error, measurement error, processing error and adjustment error. The parameters of interest concern the earnings distribution, but despite this outcome of interest, the discussion is generalizable to any question in a random sample survey of households or firms. This book then investigates questionnaire design and item nonresponse by building a response propensity model for the employee income question in two South African labour market surveys: the October Household Survey (OHS, 1997-1999) and the Labour Force Survey (LFS, 2000-2003). This time period isolates a period of changing questionnaire design for the income question. Finally, this book is concerned with how to employee income data with a mixture of continuous data, bounded response data and nonresponse. A variable with this mixture of data types is called coarse data. Because the income question consists of two parts -- an initial, exact income question and a bounded income follow-up question -- the resulting statistical distribution of employee income is both continuous and discrete. The book shows researchers how to appropriately deal with coarse income data using multiple imputation. The take-home message from this book is that researchers have a responsibility to treat data quality concerns in a statistically sound manner, rather than making adjustments to public-use data in arbitrary ways, often underpinned by undefensible assumptions about an implicit unobservable loss function in the data. The demonstration of how this can be done provides a replicable concept map with applicable methods that can be utilised in any sample survey.

This edition is the most updated since its inception, is the essential text for students and professionals working in and around epidemiology or using its methods. It covers subject areas - genetics, clinical epidemiology, public health practice/policy, preventive medicine, health promotion, social sciences and methods for clinical research.