![]() Let \(C_t\) be the random variable that counts the number of events up to time t. To start, consider continuous sequential analysis for Poisson data. None of the results are based on asymptotic theory or computer simulations. Signal and required sample size to achieve a certain power, are obtained exactly to whatever decimal precision desired, In this package, all critical values, alpha spending strategies, statistical power, expected time to Project run by the Centers for Disease Control and Prevention. MaxSPRT was developed for post-market vaccine safety surveillance as part of the Vaccine Safety Datalink Null hypothesis when there are more events than expected, no lower boundary, and an upper limit on the sample size at which time the sequentialĪnalyses end without rejecting the null. MaxSPRT uses a composite alternative hypothesis, and upper boundary to reject the Wald's Sequential Probability Ratio Test (SPRT) (Wald, 1945,47). The basis for this package is the Maximized Sequential Probability Ratio Test (MaxSPRT) statistic (Kulldorff et al., 2011), which is a variant of Real data analyses are dicussed in more details. (2021) explains the main features of the package up to version 3.3.1, where sequential test designing and In other application areas, such as clinical trials.Ī tutorial paper by Silva et al. The motivation for this package is post-market near real-time drug and vaccine safety surveillance, where the goal is to detect rareīut serious safety problems as early as possible, in many cases after only a hand full of adverse events. For a desired statistical power, it is also possible to calculate the latter. Poisson and binomial type data with a Wald-type upper boundary, which is flat with respect to the likelihood ratio function,Īnd a predetermined upper limit on the sample size. To signal when the null is rejected and the maximum sample size needed when the null is not rejected. This package contains functions for the exact calculation of critical values, statistical power, expected time Most of the sequential analysis methods found in the literature are based on asymptotic results. The critical value needed, and the corresponding expected time to signal when the null hypothesis is rejected. In the Sequential package, there are functions to calculate critical values, statistical power,Įxpected time to signal, and expected sample size at the end of the sequential analyses whether the null hypothesis was rejected or not.įor example, for any desired power, relative risk and alpha level, the package can calculate the required upper limit on the sample size (maximum length of surveillance), Than asymptotic theory or computer simulations. All results are exact, based on iterative numerical calculations, rather It is also possible to perform mixed continuous/group sequential analysis, where, for example, there is at first a bigīatch of data that arrives in one group, followed by continuous sequential analysis. For group sequential analyses, there are functions for pre-specified group sizes and for the situation when In order to specify non-flat signaling thresholds. ![]() Alternatively, it is also possible to apply a user defined alpha spending function Of the log-likelihood ratio, and on a predetermined maximum sample size. For Poisson data, the critical value is based on a Wald-type upper boundary, which is flat on the scale Off-set term to account for variable matching ratios. For binomial data, it is possible to incorporate an It is possible to analyze either Poisson type data or binomial 0/1 type data. This is different from standard statistical analysis, where a single analysis is performed On accumulating data that gradually increases the sample size. Sequential is designed for continuous and group sequential analysis, where statistical hypothesis testing is conducted repeatedly Sequential-package: Analysis Support, Critical Values, Power, Time to Signal and Sample Size for Sequential Analysis with Poisson and Binomial Data.
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