scholarly journals The Role of Theory in Field Experiments

2011 ◽  
Vol 25 (3) ◽  
pp. 39-62 ◽  
Author(s):  
David Card ◽  
Stefano DellaVigna ◽  
Ulrike Malmendier
Keyword(s):  
Economic Theory ◽  
Experimental Design ◽  
Charitable Giving ◽  
Field Experiments ◽  
Structural Parameters ◽  
Single Model ◽  
Model Studies ◽  
Model Based ◽  
Competing Models ◽  
Economics Journals

We classify all published field experiments in five top economics journals from 1975 to 2010 according to how closely the experimental design and analysis are linked to economic theory. We find that the vast majority of field experiments (68 percent) are Descriptive studies that lack any explicit model; 18 percent are Single Model studies that test a single model-based hypothesis; 6 percent are Competing Models studies that test competing model-based hypotheses; and 8 percent are Parameter Estimation studies that estimate structural parameters in a completely specified model. We also classify laboratory experiments published in these journals over the same period and find that economic theory has played a more central role in the laboratory than in the field. Finally, we discuss in detail three sets of field experiments—on gift exchange, on charitable giving, and on negative income tax—that illustrate both the benefits and the potential costs of a tighter link between experimental design and theoretical underpinnings.

Transactions Costs in Charitable Giving: Evidence from Two Field Experiments

2010 ◽  
Vol 10 (1) ◽  
Author(s):  
Steffen Huck ◽  
Imran Rasul
Keyword(s):  
Transaction Costs ◽  
Charitable Giving ◽  
Large Scale ◽  
Field Experiments ◽  
Structural Parameters ◽  
Transactions Costs ◽  
Potential Donor ◽  
Stage Design ◽  
Ex Post ◽  
Two Stages

Abstract In large-scale fundraising campaigns based on direct mailings, typically less than 5% of individuals donate to the charitable cause. We present evidence from two field experiments designed to measure the existence of transaction costs that inhibit charitable giving in such fundraising campaigns, and shed light on the nature of such transaction costs. The experiments are designed in conjunction with the Bavarian State Opera House. The first mail-out experiment was implemented over two stages using a within-subject design. We develop a theoretical framework that makes precise the identifying assumptions under which we can exploit this two-stage design to measure the following structural parameters among potential donors: (i) the share of donors who would make a strictly positive donation in the complete absence of transaction costs and (ii) the probability that a potential donor has sufficiently low transactions costs to make a strictly positive donation. Our results imply response rates to mail-out solicitations would almost double in the complete absence of transaction costs. The second field experiment provides more evidence on the nature of transaction costs. We distinguish between ex ante transaction costs, which prevent the choice problem from being considered and ex post transaction costs, which prevent choices being implemented. We find that the likelihood of a donation being made increases by 26% in response to even a small reduction in ex post transaction costs.

Iterative model‐based experimental design for spherical agglomeration processes

AIChE Journal ◽  
2021 ◽  
Author(s):  
Kanjakha Pal ◽  
Botond Szilagyi ◽  
Christopher L. Burcham ◽  
Daniel J. Jarmer ◽  
Zoltan K. Nagy
Keyword(s):  
Experimental Design ◽  
Model Based ◽  
Iterative Model

scholarly journals Evaluation of the Added Value of Regional Ensemble Forecasts on Global Ensemble Forecasts

2012 ◽  
Vol 27 (4) ◽  
pp. 972-987 ◽  
Author(s):  
Yong Wang ◽  
Simona Tascu ◽  
Florian Weidle ◽  
Karin Schmeisser
Keyword(s):  
Horizontal Resolution ◽  
Added Value ◽  
Ensemble Prediction ◽  
Small Scale ◽  
Initial Condition ◽  
Weather Variables ◽  
Single Model ◽  
Ensemble Forecasts ◽  
Model Based ◽  
Surface Weather

Abstract The regional single-model-based Aire Limitée Adaptation Dynamique Développement International–Limited Area Ensemble Forecasting (ALADIN-LAEF) ensemble prediction system (EPS) is evaluated and compared with the global ECMWF-EPS to investigate the added value of regional to global EPS models. ALADIN-LAEF consists of 16 perturbed members at 18-km horizontal resolution, while ECMWF-EPS includes 50 perturbed members at 50-km horizontal resolution. In ALADIN-LAEF, the atmospheric initial condition uncertainty is quantified by using blending, which combines large-scale uncertainty generated by the ECMWF-EPS singular-vector approach with small-scale perturbations resolved by the ALADIN breeding technique. The surface initial condition perturbations are generated by use of the noncycling surface breeding (NCSB) technique, and different physics schemes are employed for different forecast members to account for model uncertainties. The verification and comparison have been carried out for a 2-month period during summer 2007 over central Europe. The results show a quite favorable level of performance for ALADIN-LAEF compared to ECMWF-EPS for surface weather variables. ALADIN-LAEF adds more value to precipitation forecasts and has greater skill for 10-m wind and mean sea level pressure results than does ECMWF-EPS. For 2-m temperature, ALADIN-LAEF forecasts have larger spread, are statistically more consistent, but also have less skill than ECMWF-EPS due to the strong cold bias in the ALADIN forecasts. For the upper-air weather parameters, the forecast of ALADIN-LAEF has a larger spread, but the forecast skill of ALADIN-LAEF is from neutral to slightly inferior compared to ECMWF-EPS. It may be concluded that a regional single-model-based EPS with fewer ensemble members could provide more added value in terms of greater skill for near-surface weather variables than the global EPS with larger ensemble size, whereas it may have limitations when applied to upper-air weather variables.

Design and Evaluation of the Key Units in a Rapeseed Direct Seeder Integrated with Plowing-Rotating Combined Tillage

2021 ◽  
Vol 37 (6) ◽  
pp. 1005-1014
Author(s):  
Guoliang Wei ◽  
Qingsong Zhang ◽  
Biao Wang ◽  
QingXi Liao
Keyword(s):  
Field Experiments ◽  
Optimal Parameter ◽  
Structural Parameters ◽  
List Type ◽  
Oil Crops ◽  
Orthogonal Experiments ◽  
Heavy Soil ◽  
Tillage Depth ◽  
Working Parameters ◽  
Orthogonal Field

HighlightsThe seeder combined the plowing and rotating tillage to overcome the heavy soil and a large amount of straws.The plow could lift and turn the soil and straw before rotary tillage.The optimal working parameters of the seeder were obtained by orthogonal field experiments.Abstract. Rapeseed, one of the most important oil crops in China, is mainly planted in the mid-lower reaches of the Yangtze River. However, limited by the special long-term rice-rapeseed rotation, rotary tillage is applied in most of the planted areas apply instead of plow tillage, leading to a shallow arable layer. On the other hand, maintaining a high-quality seedbed for rapeseed becomes a challenge because a large amount of straw remains buried in the soil. As a solution, a rapeseed direct seeder that combines plow tillage and rotary tillage was designed. The structure of the plowing unit, whose key components were a lifting-turning plow and symmetrical plow, was analyzed based on the forming principle of the plow. Furthermore, a mechanical soil throwing model of the rotary tillage blade was built to determine the structural parameters. Then, the interaction between the rotary tillage unit and the lift-turning plow was analyzed. Finally, the performance and optimal parameters were evaluated by orthogonal field experiments. The seedbed after the operations indicated that the seeder could achieve the function of turning the soil and straw first and then rotating the soil with good passability, mixing the straw and the soil, flattening the surface of the seed bed, and stabilizing the tillage depth. Orthogonal experiments showed that the optimal working parameters of the seeder were as follows: the tillage depth was 180 mm, the equipment forward speed was 2.1 km/h, and the speed of the rotary tillage blade was 250 r/min. Under the optimal parameter combination, the power consumption of the seeder, the thickness of the tillage layer, the crop residue burial efficiency, the soil breakage efficiency, and the flatness of the seed bed surface were 30.48 kW, 231 mm, 90.88%, 93.26%, and 21.15 mm, respectively. The working performance of the seeder could meet the tillage requirements of rapeseed planting. Keywords: Direct seeder, Evaluation, Plow, Plowing-rotating combined tillage, Rapeseed.

Nudging charitable giving: Three field experiments

2017 ◽  
Vol 66 ◽  
pp. 137-149 ◽  
Author(s):  
Homa S. Zarghamee ◽  
Kent D. Messer ◽  
Jacob R. Fooks ◽  
William D. Schulze ◽  
Shang Wu ◽  
...  
Keyword(s):  
Charitable Giving ◽  
Field Experiments

scholarly journals The nonlinMIP intercomparison project: physical basis, experimental design and analysis principles

2016 ◽  
Author(s):  
P. Good ◽  
T. Andrews ◽  
R. Chadwick ◽  
J. L. Dufresne ◽  
J. M. Gregory ◽  
...  
Keyword(s):  
Experimental Design ◽  
Model Studies ◽  
Physical Mechanisms ◽  
Non Linear ◽  
Scaling Methods ◽  
Small Set ◽  
Intercomparison Project ◽  
Forcing Mechanisms ◽  
Good Signal ◽  
Co2 Forcing

Abstract. nonlinMIP aims to quantify and understand, at regional scales, climate responses that are non-linear under CO2 forcing (mechanisms for which doubling the CO2 forcing does not double the response). Non-linear responses can be large at regional scales, with important implications for understanding mechanisms and for GCM emulation techniques (e.g. energy balance models and pattern-scaling methods). However, these processes are hard to explore using traditional experiments, explaining why they have had little attention in previous studies. Some single model studies have established novel analysis principles and some physical mechanisms. There is now a need to explore robustness and uncertainty in such mechanisms across a range of models. nonlinMIP addresses this using a simple, small set of CO2-forced experiments that are able to separate linear and non-linear mechanisms cleanly, with a good signal/noise ratio – while being demonstrably traceable to realistic transient scenarios. The design builds on the CMIP5 and CMIP6 DECK protocols, and is centred around a suite of instantaneous atmospheric CO2 change experiments, with a ramp-up-ramp-down experiment to test traceability to gradual forcing scenarios. In all cases the models are intended to be used with CO2 concentrations rather than CO2 emissions as the input. The understanding gained will help interpret the spread in policy-relevant scenario projections. Here we outline the basic physical principles behind nonlinMIP, and the method of establishing traceability from abruptCO2 to gradual forcing experiments, before detailing the experimental design and finally some analysis principles. The test of traceability from abruptCO2 to transient experiments is recommended as a standard analysis within the CMIP5 and CMIP6 DECK protocols.

scholarly journals The effect of a crown shape on the activity of the processes of growth and the complexity of apple tree (Borkh) pruning in the conditions of the Piedmont zone of Crimea

2020 ◽  
pp. 242-245
Author(s):  
Виктория Сергеевна Кириченко ◽  
Нина Александровна Бабинцева ◽  
Надежда Александровна Тихомирова
Keyword(s):  
Field Experiments ◽  
Structural Parameters ◽  
High Growth ◽  
Fruit Trees ◽  
Labor Cost ◽  
Planting Density ◽  
Fruit Crops ◽  
High Productivity ◽  
Crown Shape ◽  
Dense Distribution

Основным направлением повышения продуктивности насаждений плодовых культур будет смена технологических подходов по эксплуатации садовых экосистем, основой которых является загущенное размещение плодовых деревьев, изменение формы кроны с ограничением их размеров, подбор сортов, подвоев, отвечающих требованиям плотного размещения деревьев с высокой продуктивностью, хорошим качеством плодов. Цель исследований - изучение влияния формы кроны на структурные параметры, степень облиственности и трудоемкость затрат труда при обрезке для создания интенсивных садов на слаборослых подвоях. Были проведены трехлетние полевые опыты по схеме: 1 вариант - стройное веретено (контроль); 2 вариант - безлидерная уплощенная крона; 3 вариант - трёхлидерная крона; 4 вариант - французская ось при плотности посадки 2500 дер./га (4 х 1 м). Объектом исследований являлись сорта яблони Бреберн, Джалита, Ренет Симиренко на подвое ЕМ IX в саду с капельным поливом. Работа проводилась по методикам полевых опытов с плодовыми культурами. Установлено, что высокая ростовая активность наблюдалась у сорта Ренет Симиренко независимо от формы кроны, где параметры варьировали от 0,71 м до 1,06 м. Структура плодообразующей древесины дерева зависит от биологических особенностей сорта и формы кроны. На третий год после посадки сада в кронах деревьев свободного веретена и французской оси сформировано наибольшее количество генеративных образований от 20,3 и 24,7% (Джалита, Бреберн) до 23,3 и 25,6% (Ренет Симиренко). Трудоемкость обрезки зависит от сорта, формы кроны и структуры обрастающей древесины. Максимальные затраты труда применяет один человек на обрезку деревьев сорта Джалита с трехлидерной кроной (25,6 чел.-час./га) и безлидерной уплощенной кроной (22,9 чел.-час./га). На обрезку сада деревьев с кроной по типу французской оси требуется 1,0 и 1,4 дня одному человеку или 7,2 (Джалита) и 9,5чел.- час./га (Ренет Симиренко), что в 1,9 и 2,2 раза меньше, чем на обрезку деревьев по типу стройного веретена (контроль). Область применения - садоводческие с.-х. предприятия всех форм собственности, садоводы - любители, специалисты The main direction of improving the productivity of plantations of fruit crops will be a change of technological approaches to the use of garden ecosystems, based on dense placement of fruit trees, changing the shape of the crown cap size, selection of varieties, rootstocks, meeting the requirements of a dense distribution of trees with high productivity, good fruit quality. The purpose of the research was to study the effect of crown shape on structural parameters, the degree of foliage and labor coefficient of pruning for the creation of intensive gardens on dwarf rootstocks. We carried out three-year field experiments according to the scheme: option 1 - slender spindle (control); option 2 - leaderless flattened crown; option 3 - triple leaders crown; option 4 - French axe, when planting density was 2500 trees/ha (4 х 1 м). The varieties ‘Braeburn’, ‘Dzhalita’, ‘Renet Simirenko’ on the rootstock EM IX in the garden with drip irrigation were the object of research. The study was performed according to the techniques of field experiments with fruit crops. It was found that high growth activity was observed for the variety ‘Renet Simirenko’, regardless the form of the crown, with parameters ranged from 0.71 m to 1,06 м. The structure of carpogenous wood depended on the biological characteristics of variety and crown shape. In the third year after planting the garden in the trees of control and French axe the greatest number of generative formations from 20.3 and 24.7% (‘Dzhalita’, ‘Braeburn’) to 23.3 and 25.6% (‘Renet Simirenko’) were developed. The complexity of pruning depended on the variety, the crown shape and the structure of the overgrown wood. Maximum labor cost one person spends for pruning the variety ‘Dzhalita’ with triple leader crown (25.6 man-hour/ha) and leaderless flattened crown (22.9 man-hour/ha). Pruning trees with French axe type of crown required 1.0 and 1.4 days per one person or 7.2 (‘Dzhalita’) and 9.5 man-hour/ha (‘Renet Simirenko’), which was 1.9 and 2.2 times less than the pruning according to the control. The scopes of the research are horticultural agricultural enterprises of all forms of ownership, gardener amateurs and experts.

scholarly journals Altruism and Egoism/Warm Glow in Economics and Psychology: Building a Bridge Between Different Experimental Approaches

2017 ◽  
Author(s):  
Mark Ottoni-Wilhelm
Keyword(s):  
Experimental Design ◽  
Charitable Giving ◽  
Experimental Testing ◽  
Helping Behavior ◽  
Experimental Designs ◽  
Warm Glow ◽  
Systematic Description ◽  
Experimental Approaches

The same dual–motive theory that combines altruism and egoism/warm glow is used in economics to study charitable giving and in psychology to study helping behavior. However, the two disciplines have taken different approaches to experimental testing. This paper builds a bridge between the different experimental approaches. For economists, the importance of this bridge is that it leads to a systematic description of six specific types of egoism/warm glow, and further suggests experimental designs that could be used to investigate warm glow motives in charitable giving. For psychologists, the bridge is important because the experimental design in economics suggests a way to test, directly rather than indirectly, the empathy–altruism hypothesis.

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