Are self-reported fertility preferences biased? Evidence from indirect elicitation methods.

Desired fertility measures are routinely collected and used by researchers and policy makers, but their self-reported nature raises the possibility of reporting bias. In this paper, we test for the presence of such bias by comparing responses to direct survey questions with indirect questions offering a varying, randomized, degree of confidentiality to respondents in a socioeconomically diverse sample of Nigerian women ([Formula: see text]). We find that women report higher fertility preferences when asked indirectly, but only when their responses afford them complete confidentiality, not when their responses are simply blind to the enumerator. Our results suggest that there may be fewer unintended pregnancies than currently thought and that the effectiveness of family planning policy targeting may be weakened by the bias we uncover. We conclude with suggestions for future work on how to mitigate reporting bias.

Preparing for a pandemic: spending dynamics and panic buying during the COVID-19 first wave.

In times of heightened uncertainty, consumers face incentives to build up precautionary stocks of essential supplies. We study consumer spending dynamics during one such time, the first infection wave of the COVID-19 pandemic, using household scanner data covering fast-moving consumer goods in the United Kingdom. We document large increases in demand for storable products, such as food staples and household supplies, in the days before lockdown. Households in all socio-economic groups exhibit unusually high demand pre-lockdown, but there is a clear gradient, with the largest demand spikes for wealthier households. Although stories of people purchasing extreme amounts received a lot of attention, higher aggregate demand was mainly driven by more households than usual choosing to buy storable products, with only small increases in average quantities bought on a given trip. Temporary limits on the number of units per transaction, introduced following the demand spike, are therefore unlikely to lead to the avoidance of stock-outs.

Inference in a Synchronization Game with Social Interactions.

This paper studies inference in a continuous time game where an agent's decision to quit an activity depends on the participation of other players. In equilibrium, similar actions can be explained not only by direct influences but also by correlated factors. Our model can be seen as a simultaneous duration model with multiple decision makers and interdependent durations. We study the problem of determining the existence and uniqueness of equilibrium stopping strategies in this setting. This paper provides results and conditions for the detection of these endogenous effects. First, we show that the presence of such effects is a necessary and sufficient condition for simultaneous exits. This allows us to set up a nonparametric test for the presence of such influences which is robust to multiple equilibria. Second, we provide conditions under which parameters in the game are identified. Finally, we apply the model to data on desertion in the Union Army during the American Civil War and find evidence of endogenous influences.

Improvement in insulin sensitivity and ß-cell function following ileal interposition with sleeve gastrectomy in type 2 diabetic patients: potential mechanisms.

INTRODUCTION: Bariatric surgery in morbidly obese type 2 diabetic (T2DM) patients is associated with high rates of diabetes remission. We investigated the mechanisms of the anti-diabetic effect of the laparoscopic ileal interposition with sleeve gastrectomy (LII-SG) in normal weight (NW), overweight (OW) and obese (OB) T2DM patients. METHODS: Ninety-four patients (aged 54 ± 8 years) with long-standing (median 10 years), treated diabetes (median HbA(1c) = 8.6%), who were NW (15), OW (64) or OB (15) based on BMI, underwent LII-SG. Insulin sensitivity and parameters of ß-cell function were measured from an Oral Glycaemic Tolerance Test pre- and post-operatively. RESULTS: At a median of 13.4 months post-operatively, weight loss averaged 9.4 ± 1.3, 16.8 ± 0.8 and 23.2 ± 1.7 kg in NW, OW and OB subjects, respectively (p < 0.0001). Insulin sensitivity was fully restored (395 [108] vs 208 [99] ml min⁻¹ m⁻²), fasting insulin secretion rate decreased (68 [52] vs 146 [120] pmol min⁻¹ m⁻²) and total insulin output increased (52 [26] vs 39 [28] nmol m⁻², all p ≤ 0.001). ß-cell glucose sensitivity doubled (37 [33] vs 18 [24] mol min⁻¹ m⁻² mM⁻¹, p < 0.0001). The only parameter predicting remission of diabetes was a lower baseline insulin sensitivity (p = 0.005). CONCLUSIONS: LII-SG induced changes on T2DM by mechanisms in part distinct from weight loss, principally involving restoration of insulin sensitivity and improvement of ß-cell function.

Prospective randomized controlled trial comparing 2 versions of laparoscopic ileal interposition associated with sleeve gastrectomy for patients with type 2 diabetes with BMI 21-34 kg/m(2).

BACKGROUND: The objective of the present study was to prospectively evaluate the results of 2 versions of laparoscopic ileal interposition (II) and sleeve gastrectomy (SG) for the treatment of patients with type 2 diabetes mellitus and body mass index of 21-34 kg/m(2). METHODS: The laparoscopic procedures were prospectively and randomly performed in 38 patients. Of the 38 patients, 18 underwent the first version (II-SG) and 20 underwent the second version in which a diversion of the second portion of the duodenum was applied (II-DSG) and a segment of ileum was interposed into the proximal duodenum. The groups were comparable regarding age (56 and 50 years); gender (13 men and 5 women and 14 men and 6 women); weight (78 and 86 kg); mean BMI (27 and 29 kg/m(2)); duration of type 2 diabetes mellitus (10.1 and 9.2 years); the presence of dyslipidemia (12 and 8 patients), micro- and macroalbuminuria (9 and 9 patients), hypertension (8 and 15 patients), and retinopathy (5 and 8 patients); and the use of antidiabetic medications and the hemoglobin A1c level (8.6% and 8.4%). All patients were followed up for >or=2 years. RESULTS: The mean hospital stay was 3.4 days for the II-SG and 3.5 days for the II-DSG group. No patient required reoperation. All patients in both groups achieved lower levels of hemoglobin A1c. In the II-SG group, the mean hemoglobin A1c level was 6.35% (range 4.9-8.1). In the II-DSG group, the mean hemoglobin A1c level was 5.39% (range 4.2-6.5%). The mean BMI decreased in both groups to 22.2 kg/m(2) in the II-SG group and 22.7 kg/m(2) in the II-DSG group. Normal cholesterol levels (<200 mg/dL) were observed in 95% of the II-SG group and 100% of the II-DSG group. The triglycerides were lower than 150 mg/dL in 73% of the II-SG group and 90% of the II-DSG group after 24 months. CONCLUSION: Laparoscopic II-SG and II-DSG were safe and effective operations for controlling type 2 diabetes mellitus in a nonobese (BMI 21-34 kg/m(2)) population.