PASS 2019 Update

Use the button(s) below to download the PASS 2019 installation file. If PASS 2019 is not yet installed on your computer, this will install the full version. If you already have PASS 2019 installed, this will update your current installation to the newest version. Your personal files will not be affected.

PASS 2019 Download

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File: PASS2019Setup_v19_0_8.exe
Size: 193.16 MB
Current Version: 19.0.8
Released: February 19, 2021

Click here for minimum System Requirements


PDF documentation for PASS 2019 is installed with the software and can be accessed through the Help System. The documentation is not available online at this time.

Update Release Notes

This page lists the changes that have been made to PASS 2019 since it was released.

Version: 19.0.8

Released: February 19, 2021

1. 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).

2. 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: 19.0.7

Released: January 28, 2021

1. Corrected an error in the two Mendelian Randomization procedures that caused the reported value for N when searching for sample size to be off by 1 in some cases.

2. Corrected fatal errors that were occurring when editing lines, colors, and symbols in Group-Sequential Boundary Plots.

3. General startup stability improvements.

Version: 19.0.6

Released: August 27, 2020

1. Mediation procedures have been corrected to allow for negative value input in all appropriate cases. Before the corrections were made, the sample size search would not converge.

2. Corrected an error in the display of input headings for the One-Sample Logrank Tests and One-Sample Tests for Exponential Hazard Rate procedures. The "Alpha" heading was being displayed in error on the panel when the Solve For was set to "Effect Size".

3. Corrected output typos in the two-sided null hypothesis for the Two-Sample T-Tests Assuming Equal Variance procedure, Two-Sample T-Tests Allowing Unequal Variance procedure, and the Mann-Whitney U or Wilcoxon Rank-Sum Tests. The null hypothesis for the two-sided test was incorrectly stated as H0: δ ≠ 0 instead of H0: δ = 0. This error did not affect calculations.

Version: 19.0.5

Released: May 22, 2020

1. Corrected an error in the Group-Sequential simulation procedures that required the user to repeatedly press “Abort” in order to Abort a procedure run.

2. Corrected an error in the Cox Regression procedure when solving for power with B = 0. PASS was returning Beta for Power instead of returning Alpha for Power.

3. Corrected an error that caused plots with Extra Symbols added outside the bounds of the plot lines to become tiny. Extra symbols outside of the plot boundaries are not displayed.

4. The validation example (based on Lakatos, 1988) for the Two-Group Survival Comparison Tests (Simulation) procedure and the Logrank Tests procedure had the noncompliance and drop-in rates reversed. This was fixed in the documentation and in the validation example templates. The fix did not result in a change to the estimated sample size.

5. Corrected minor typos in the power formula in the documentation of the Equivalence Tests for the Difference Between Two Correlated Proportions procedure.

Version: 19.0.4

Released: February 10, 2020

1. An error in the Mixed Models Tests for Two Proportions in a 3-Level Hierarchical Design (Level-3 Randomization) procedure was corrected. The input screen was not working properly when Solve For was set to “M.”

2. An error in the Mixed Models Tests for Two Means in a 2-Level Hierarchical Design (Level-2 Randomization) procedure was corrected. The error occurred when a search for “M” was run. M and power were correct, but K2 and N2 were not.

3. Fixed errors in the Equivalence Tests for Two Means (Simulation) and Equivalence Tests for Paired Means (Simulation) procedures. When using symmetric equivalence limits and multiple values for M1, only the first scenario had symmetric limits.

4. Corrected a typo in the formula for Power using W5 on page 437-4 of the documentation of the Tests for the Ratio of Two Poisson Rates procedure. The formula incorrectly indicated that Power(W5) = 1 - φ(…). It has been corrected to Power(W5) = φ(…) so that it matches what is actually being calculated. This typo did not affect the calculated results of the procedure.

Version: 19.0.3

Released: October 25, 2019

1. Corrected an error in the calculation of Power when solving for Sample Size in the Reliability Demonstration Tests of One Proportion with Adverse Events procedure. Type II Error (Beta) was being reported instead of Power. This has been corrected. Note that when solving for Alpha, the correct Power was reported.

2. Corrected a minor typo in the documentation for the Tests for One Proportion procedure related to the value of c in the power formulas for the continuity-corrected tests.

3. The formula for power in the option [3] of Post-Marketing Surveillance changed in the 4th Edition of Machin’s sample size book (2018). PASS 2019 was upgraded to use the new formula. Note that the new formula only gives different results when the sample sizes of the two groups are not equal.

4. Fixed an Error in the "Conditional Power of Tests for the Difference Between Two Proportions" procedure. The conditional power was computed incorrectly when Input Type = "Differences". This has been corrected.

Version: 19.0.2

Released: May 24, 2019

1. Added the ability for the software to periodically check online for updates and notify the user when an update is available. This new capability is controlled through System Options.

2. Corrected an error in the Simple Linear Regression procedures that caused the search to fail when solving for slope and using σʏ as the Standard Deviation of Residuals Input Type.

3. Fixed a “Subscript out of range” error in the Tests for Two Proportions in a Repeated Measures Design procedure that occurred when Group Allocation was set to “Enter total sample size and percentage in Group 1” and Definitions were being output in the report.

4. Minor documentation changes to correct typos.

Version: 19.0.1

Released: March 23, 2019

1. Initial Release of PASS 2019.

"I have used NCSS since it was NCSS 2000. Absolutely love it."

Dr. William Kennedy, Consultant

“I’ve used NCSS since 1986 and PASS since 1997. The utility, precision, documentation, output and ease-of-use of your products are the best in the business. Thank you!”

Tim Gohmann, Ph.D.