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Adaptive survey designs are increasingly used by survey practitioners to counteract ongoing declines in household survey response rates and manage rising fieldwork costs. This paper reports findings from an evaluation of an early-bird incentive (EBI) experiment targeting high-effort respondents who participate in the 2019 wave of the US Panel Study of Income Dynamics. We identified a subgroup of high-effort respondents at risk of nonresponse based on their prior wave fieldwork effort and randomized them to a treatment offering an extra time-delimited monetary incentive for completing their interview within the first month of data collection (treatment group; N  = 800) or the standard study incentive (control group; N  = 400). In recent waves, we have found that the costs of the protracted fieldwork needed to complete interviews with high-effort cases in the form of interviewer contact attempts plus an increased incentive near the close of data collection are extremely high. By incentivizing early participation and reducing the number of interviewer contact attempts and fieldwork days to complete the interview, our goal was to manage both nonresponse and survey costs. We found that the EBI treatment increased response rates and reduced fieldwork effort and costs compared to a control group. We review several key findings and limitations, discuss their implications, and identify the next steps for future research. [ABSTRACT FROM AUTHOR]

In theory, offering each sample member the mode sequence that maximizes their response propensity should increase the response rate and/or reduce the amount of nonresponse follow-up relative to a design that offers all sample members the same mode sequence. However, for this sort of tailoring to be feasible in a cross-sectional survey, it must be possible to use data available prior to data collection (e.g. on the sampling frame) to predict sample members' "mode-sensitivity"—the effect of the offered mode sequence on response propensity. Using data from randomized experiments incorporated into the 2016 and 2019 cycles of the National Household Education Survey, we evaluate whether data appended to an address-based sampling (ABS) frame can accurately predict the sensitivity of household-level response behavior to the initial offer of a paper questionnaire instead of a web instrument and whether a modeled-mode design that tailors the offered mode sequence (web-push vs. paper-only) based on the resulting predictions improves household-level data collection outcomes relative to a uniform web-push design. We find that several characteristics available on the ABS frame show statistically significant interactions with the offered mode sequence in determining the probability of response to initial survey mailings. Consequently, relative to a uniform web-push design, the modeled-mode design increased the response rate to early mailings and reduced the number of mailings required per response. However, the modeled-mode design did not meaningfully increase the final response rate, nor did it lead to a substantial reduction in indicators of nonresponse bias. [ABSTRACT FROM AUTHOR]

Early‐phase dose‐finding clinical trials are often subject to the issue of late‐onset outcomes. In phase I/II clinical trials, the issue becomes more intractable because toxicity and efficacy can be competing risk outcomes such that the occurrence of the first outcome will terminate the other one. In this paper, we propose a novel Bayesian adaptive phase I/II clinical trial design to address the issue of late‐onset competing risk outcomes. We use the continuation‐ratio model to characterize the trinomial response outcomes and the cause‐specific hazard rate method to model the competing‐risk survival outcomes. We treat the late‐onset outcomes as missing data and develop a Bayesian data augmentation method to impute the missing data from the observations. We also propose an adaptive dose‐finding algorithm to allocate patients and identify the optimal biological dose during the trial. Simulation studies show that the proposed design yields desirable operating characteristics. [ABSTRACT FROM AUTHOR]

Covariate‐adaptive randomization (CAR) is widely used in clinical trials to balance treatment allocation over covariates. Over the past decade, significant progress has been made on the theoretical properties of covariate‐adaptive design and associated inference. However, most results are established under the assumption that the covariates are correctly measured. In practice, measurement error is inevitable, resulting in misclassification for discrete covariates. When covariate misclassification is present in a clinical trial conducted using CAR, the impact is twofold: it impairs the intended covariate balance, and raises concerns over the validity of test procedures. In this paper, we consider the impact of misclassification on covariate‐adaptive randomized trials from the perspectives of both design and inference. We derive the asymptotic normality, and thereby the convergence rate, of the imbalance of the true covariates for a general family of covariate‐adaptive randomization methods, and show that a superior covariate balance can still be attained compared to complete randomization. We also show that the two sample t‐test is conservative, with a reduced Type I error, but that this can be corrected using a bootstrap method. Moreover, if the misclassified covariates are adjusted in the model used for analysis, the test maintains its nominal Type I error, with an increased power. Our results support the use of covariate‐adaptive randomization in clinical trials, even when the covariates are subject to misclassification. [ABSTRACT FROM AUTHOR]

This paper deals with the design of the likelihood continual reassessment method, which is an increasingly widely used model-based method for dose-finding studies. It is common to implement the method in a two-stage approach, whereby the model-based stage is activated after an initial sequence of patients has been treated. While this two-stage approach is practically appealing, it lacks a theoretical framework, and it is often unclear how the design components should be specified. This paper develops a general framework based on the coherence principle, from which we derive a design calibration process. A real clinical-trial example is used to demonstrate that the proposed process can be implemented in a timely and reproducible manner, while offering competitive operating characteristics. We explore the operating characteristics of different models within this framework and show the performance to be insensitive to the choice of dose-toxicity model. [ABSTRACT FROM PUBLISHER]

This paper is motivated by a phase I-II clinical trial of a targeted agent for advanced solid tumors. We study a stylized version of this trial with the goal to determine optimal actions in each of two cycles of therapy. A design is presented that generalizes the decision-theoretic two-cycle design of Lee and others (2015. Bayesian dose-finding in two treatment cycles based on the joint utility of efficacy and toxicity. Journal of the American Statistical Association, to appear) to accommodate ordinal outcomes. Backward induction is used to jointly optimize the actions taken for each patient in each of the two cycles, with the second action accounting for the patient's cycle 1 dose and outcomes. A simulation study shows that simpler designs obtained by dichotomizing the ordinal outcomes either perform very similarly to the proposed design, or have much worse performance in some scenarios. We also compare the proposed design with the simpler approaches of optimizing the doses in each cycle separately, or ignoring the distinction between cycles 1 and 2. [ABSTRACT FROM AUTHOR]