# PASS 2021 Update

Use the button(s) below to download the PASS 2021 installation file. If PASS 2021 is not yet installed on your computer, this will install the full version. If you already have PASS 2021 installed, this will update your current installation to the newest version. Your personal files will not be affected.## PASS 2021 Download

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File: PASS2021Setup_v21_0_8.exe

Size: 246.28 MB

Current Version: 21.0.8

Released: May 4, 2023

Click here for minimum System Requirements

## Documentation

## Update Release Notes

This page lists the changes that have been made to PASS 2021 since it was released.

### Version: 21.0.8

Released: May 4, 2023

1. Corrected a non-useful error message in the Logrank Tests and Non-Inferiority Logrank Tests procedures. The user now gets an informative error message if they input Total Time < Accrual Time that indicates that Total Time must be ≥ Accrual Time.

2. Corrected an error in the Tests for Two Ordered Categorical Variables (Proportional Odds) procedure. The software was interpreting the odds ratio (OR) as Odds1/Odds2 instead of Odds2/Odds1 as indicated in the documentation. The procedure now correctly interprets OR as Odds2/Odds1. Some minor typos and the example results in the documentation for this procedure have also been corrected.

3. Corrected an issue with the Simple Linear Regression procedures when solving for sample size. If the effect size is large resulting in a very small required sample size (i.e., 4 or less), the algorithm would not find the right sample size--it would report a required sample size of 2 even though the sample size is required to be 3 or more in the Simple Linear Regression procedures.

### Version: 21.0.7

Released: January 23, 2023

1. In the Confidence Intervals for One-Way Repeated Measures Contrasts procedure, there is a Multivariate option and a Univariate option. A bug was causing an error whenever the Univariate option was selected. Now, both options can be run with no error.

2. In the Mann-Whitney U or Wilcoxon Rank-Sum Tests for Non-Inferiority and Mann-Whitney U or Wilcoxon Rank-Sum Tests for Superiority by a Margin procedures, the sample sizes were not reported correctly in the summary statements when solving for effect size. Now, the sample sizes are consistent with those shown in the table.

3. In the Non-Inferiority Tests for the Difference of Two Means in a Higher-Order Cross-Over Design procedure, if "Specify sigma as sigmaw or sigmab and row" was set to "sigmab and row", the sigmab did not read in correctly and the procedure produced incorrect results. This was fixed to read in the sigmab value, and the results are now correct.

4. In the six group-sequential survival (simulation) procedures, the accrual parameter, if different from 0, was not implemented correctly. If the accrual parameter was other than 0 (or the "Percent of T0 Until 50% are Accrued" was other than 50), the starting times for the simulations were generated incorrectly. This was fixed so that the start times are distributed according to the truncated Exponential distribution, as indicated in the option info.

5. Corrected an error in power calculation for the Equivalence Tests for Two Means in a Cluster-Randomized Design procedure. When Test Statistic was set to “T-Test Based on Number of Clusters” (not the default) and K1 was not equal to K2, the power was calculated using the wrong degrees of freedom. This resulted in the power being slightly off the correct value.

### Version: 21.0.6

Released: August 9, 2022

1. Corrected the formula for the SD of the Uniform Distribution in the documentation for the Data Simulator procedure. The procedure calculations were not affected.

2. Corrected an error in the Tests for One-Sample Sensitivity and Specificity procedure. For some language settings (e.g., Hungarian) the N1 and N sample size values would appear mashed together in the Numeric Results table making it appear that only one large sample size was computed.

3. Fixed the Accrual Time (Integers Only) input option in the Two-Group Survival Comparison Tests (Simulation) and Group-Sequential Logrank Tests (Simulation) (Legacy) procedures so that decimal numbers are not included as possible options in the dropdown. The procedures were also updated so that decimal number are correctly rounded to whole numbers before calculation.

4. Corrected an error in the Non-Zero Null Tests for Simple Linear Regression using ρ² procedure. For some combinations of ρ0² and ρ1², solving for N (Sample Size) would return no results.

5. Corrected an issue in the Confidence Intervals for Kappa procedure. When Interval Type was set to something other than Two-Sided, the software was not reading the Distance from κ to Limit option correctly. Instead it was reading and using the hidden Width of Confidence Interval option value in its place.

6. In the Confidence Intervals for an Exponential Lifetime Percentile procedure, the Width of Confidence Interval was limited to values between 0 and 2. It was fixed to correctly allow for all values greater than 0.

7. Corrected an error in the following procedures: Tests for Two Means in a Repeated Measures Design, Tests for Two Proportions, Fisher's Exact Test for Two Proportions, Non-Inferiority (Superiority by a Margin, Equivalence, Non-Zero Null) Tests for the Difference (Ratio, Odds Ratio) Between Two Proportions, Tests for Two Independent Sensitivities, Non-Inferiority (Superiority by a Margin) Tests for Vaccine Efficacy using the Ratio of Two Proportions. When solving for sample size with Group Allocation set to “Enter R” or “Enter percentage in group 1”, the reported sample sizes might have been slightly off (usually by only 1 subject) due to incorrect rounding of the sample sizes.

### Version: 21.0.5

Released: February 15, 2022

1. Modified the allowable ranges for Cluster Size parameters M and m in the three Stepped-Wedge Cluster-Randomized Design procedures. The restriction that both parameters be ≥ 2 was found to be unnecessary. Now both parameters have allowed range of > 0.

2. An error in the “Mann-Whitney or Wilcoxon Rank-Sum Tests (Simulation)” and the “Tests for Two Means (Simulation)” routines has been corrected. The error caused the mean differences to be reported incorrectly in cases where the distribution’s first parameter was not the mean. The power calculations were correct.

### Version: 21.0.4

Released: January 20, 2022

1. Corrected an error that caused the text in some single-value dropdown inputs on the Procedure Window not to be read correctly after selecting an item from the dropdown list.

2. Corrected an error in the Non-Inferiority (and Equivalence) Tests for the Difference (and Ratio) of Two Correlated Proportions procedures. When one of the cell proportions was zero, the software would incorrectly indicate an undefined table in some cases.

3. Corrected an issue with graphics dropdown buttons when using Windows 11. Dropdown buttons on plot format windows would display two images (one slightly offset from the other).

4. With this update, PASS 2021 is considered to be fully compatible with Windows 11.

5. Corrected the documentation for the Bland-Altman Method for Assessing Agreement in Method Comparison Studies procedure. NCT() was incorrectly stated as the inverse of Student’s non-central t distribution. This has been fixed such that NCT() is correctly stated as the cumulative distribution function of Student’s non-central t distribution.

### Version: 21.0.3

Released: August 30, 2021

1. Corrected an error in displaying the Detail Numeric Reports in the Non-Inferiority Logrank Tests procedure.

2. Corrected an error in all GEE Tests procedures. The correlation matrix was not computed correctly when using Damped Exponential as the Pattern of ρ’s Across Time.

3. Corrected an error that occurred when parsing user-entered TO BY lists (e.g., "-2 to 2 by 0.1"). In some cases, rounding errors were causing unexpected results.

4. Corrected an error in the Superiority by a Margin Tests for Two Means in a Cluster-Randomized Design procedure when solving for M1. The search now converges.

5. Corrected an error in the Tests for Two Proportions in a Stepped-Wedge Cluster-Randomized Design procedure when solving for Effect Size with Effect Size Input Type set to Differences, Ratios, or Odds Ratios. The search now gives the correct result.

6. Corrected an error in the Tests for Two Means in a Stepped-Wedge Cluster-Randomized Design procedure when solving for Effect Size with Effect Size Input Type set to Differences. The search now gives the correct result.

7. Corrected an error in the Tests for Two Poisson Rates in a Stepped-Wedge Cluster-Randomized Design procedure when solving for Effect Size with Effect Size Input Type set to Differences or Rate Ratios. The search now gives the correct result.

8. Fixed the Dropout-Inflated Sample Size report in the Equivalence Tests for the Mean Ratio in a Three-Arm Trial (Normal Data) (Simulation) procedure. Results are now shown for all 3 groups.

9. Fixed the group allocation in the Equivalence Tests for the Mean Ratio in a Three-Arm Trial (Normal Data) (Simulation) procedure when solving for Sample Size. The allocation for nᴘ is now applied correctly when using unequal group allocation.

### Version: 21.0.2

Released: February 19, 2021

1. Minor documentation updates.

2. Corrected an error in the Logrank Tests procedure. When using Mortality input, power and sample size were not computed correctly when entering M1 (Mortality - Control) and MR (Mortality Ratio = M2/M1). Power and sample size were correct when entering M1 (Mortality - Control) and M2 (Mortality - Treatment).

3. Corrected “Unhandled exception…” errors that occurred when opening PASS procedures in Windows 10 when the Microsoft Region language option **Beta: Use Unicode UTF-8 for worldwide language support** is active. (To determine if the option is active on your computer, see the steps below.)

Having the **Beta: Use Unicode UTF-8 for worldwide language support** option active may lead to other errors. We recommend that the option be disabled when using PASS.

To disable this option in Windows 10, perform the following steps with administrator rights on your computer:

a. Close all open documents and programs on your computer.

b. Press the **Windows** key.

c. Type “**Settings**.”

d. Select **Time & Language**.

e. Click **Language**.

f. Under **Related settings**, click **Administrative language settings**.

g. On the **Region** window, click the **Administrative** tab.

h. Click **Change system locale**. (Here you will need administrator rights.)

i. Clear the **Beta: Use Unicode UTF-8 for worldwide language support** checkbox.

j. Click **OK**.

k. Restart your computer.

### Version: 21.0.1

Released: January 29, 2021

1. Initial Release of PASS 2021.