Special Purity Tolerances

To all Seed Analysts, Seed Technologists, and Seed Control Officials,

Now available is the AOSA Special Tolerances Computer Program for automatically calculating purity tolerances of seed mixture using Tables 14D and 14E. In consultation with the AOSA Purity Subcommittee and the AOSA Statistics Committee, the program was developed by Andrew Meyer, a Computer Science major at California State University, Sacramento. Since the 2015 AOSA/SCST Annual Meeting, two rounds of beta testing have been conducted. Based on comments received, the special tolerance calculation program has been upgraded significantly adding a more extensive user guide and the automatic tolerance determination using Table 14B in cases when particle-weight ratio is 1.45 or less.

 Once you download the zip file from the website you will need to decompress (unzip) the file.  To do this: (1) right click on the zip file folder; (2) select ‘extract’ from the menu; (3) when prompted choose a destination for the “AOSA Special Tolerances” folder; and (4) click either yes/ok/extract to produce an uncompressed folder containing all the essential files.  When you open the AOSA Special Tolerances file folder, it’s important that you first read the ‘Read Me’ text file and review the ‘For Users’ PowerPoint.  The ‘User Manual’ is also accessible from the Java window display for the special tolerances program (top tab on right-hand side of display window).
On your initial use of the computer program I would like you to compare your own calculations of special tolerances on any mixtures of your choosing to that of the same mixtures using the computer program.  I suggest that you do all your calculations first and then use the program.  The mixtures you use may have as many components as you would like to try.  I encourage using mixtures with two or more components with a wide range of particle sizes.

Data you will need to supply when using the program:

  1. Label information (kind of seed, pure seed percentages).
  2. Results of second test (your test results).
  3. Number of seeds per gram (found in Table 2A) for each component.

Please e-mail Andrew (meyer95826@gmail.com) if you have any questions or comments about the program.  Please include me as a ‘cc’ on your email so I can track comments and questions.

Also, to avoid confusion, if you participated in prior beta testing rounds please remove the old version of the program from your computer and discard the CDs.

For folks that are unable to download the program file from the website due to IT policy restrictions at your worksite, please contact me and I will provide the program file on a CD.

Good luck with your Special Tolerance calculations!


Deborah Meyer
AOSA Purity Committee Chair
California Department of Food & Agriculture
Plant Pest Diagnostics Center – Seed Science Laboratory
Meadowview Road
Sacramento, CA 95832-1448


Program Information

Click here to download the full PDF.