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Skills of Central Pennsylvania: Using Minitab to Curb Supplier Defects

Skills of Central Pennsylvania is a nonprofit organization that provides vocational, rehabilitative, and social opportunities for individuals with disabilities. The organization’s Employment Services Division specializes in matching the needs of employers in central Pennsylvania to the abilities of the people Skills serves. The Skills Industrial Centers workforce primarily staffs for manufacturing companies, and is known for their high-quality work, low turnover rates, and willingness to go above and beyond employer expectations with their service. So when the Skills industrial workforce noticed that one of their employer’s manufacturing processes could be improved, they enlisted the help of Minitab Statistical Software.

The Challenge

Individuals from the Centre Region branch of the Skills workforce were hired by a local manufacturer to assemble 4 ml. and 2 ml. vials for the production of liquid chromatography columns that are used in chemical laboratories across a multitude of industries. These vials act as sample vessels for testing different substance molecules to ensure they meet strict industry specifications. Under the direction of Mary Kay Fultz, vocational and industrial services manager for the Centre Regional Office, Skills workers assemble vials by attaching blister caps to vial bottle tops. These caps must be properly aligned with threading placed on the sides of the bottles. However, Teresa Weyant, Skills team leader and company liaison, and the workers quickly discovered a defect in the threading of certain vial bottles that caused several blister caps not to fit, so the vials could not tighten properly. In these cases, the bottles with defective threading were discarded and had to be replaced with new bottles that would allow the caps to fit securely. Fultz and the team wanted to track and report the number of defective units to the vial bottle supplier in order to prevent the manufacturer from continuing to pay for the rejects.

Skills of Central Pennsylvania trusted Minitab Statistical Software to help them analyze data to improve vial assembly processes.

How Minitab Helped

Fultz and the Skills quality improvement team collected data on the number of defective bottles its workers found in each box delivered by the supplier. The team recorded the number of rejects in each box and entered that information into a Minitab worksheet, which put them in position to quickly analyze the data and find out more about the defective supply.

Fultz knew she wanted the analysis to help her examine the proportion of defective vial bottles and assess the stability of the process, but she wasn’t quite sure where to begin. With the support of the Minitab Assistant, a menu-based tool that guides users step-by-step through their statistical analysis, Fultz was able to follow an interactive decision tree to determine which analysis to use to examine the data. She selected the P chart option because she and her team were investigating rejected items, and then quickly completed a simplified dialog box before being presented with not only the P chart, but also detailed reports that included interpretation of the results.

The Assistant’s comprehensive reports made it easy for the Skills quality team to verify their analyses met statistical guidelines.

Fultz is not a statistician or quality practitioner by trade, but she says using Minitab Statistical Software couldn’t have been easier.

"With the help of the Assistant menu, we were guided completely through our analysis—from start to finish," Fultz says. "The built-in interpretation was extremely helpful and made understanding and responding to the analysis easy."

The quality team at Skills was able to use the Assistant menu to create control charts, which helped them investigate the proportion of defective vial bottles delivered from a supplier.

The Results

The results of the analysis Fultz completed using the Assistant revealed the proportion of defective vial bottles was not stable, and the control chart clearly showed the team the out-of-control subgroups in relation to the defined upper and lower control limits. The chart made it easy to pinpoint problem areas, as well as patterns and trends in the data. The results even showed the Skills quality team that one box included more than 20% defective vial bottles.

The Assistant also provided the team with comprehensive reports, which outlined the exact number of out-of-control subgroups and showed the team that the analysis met various statistical guidelines, such as checks for accuracy and precision.

Once they completed their analysis, the Skills team was able to confidently and clearly communicate that there was an issue with the vials to both the manufacturer and the supplier.

"Before Minitab, we never looked at the number of rejected units," says Fultz. "Now we are able to keep track of the defects and regularly contact the supplier to amend the billing—which saves the manufacturer money."

Fultz also says the manufacturer is grateful that Skills started tracking and analyzing the defective vials. And now that the supplier is aware of the defects, they are working on improving the quality of their processes and providing the manufacturer with boxes of defect-free vial bottles.

Skills is proud to help the manufacturers it serves to improve quality, and considers this project the first of many. "Next, we plan to use Minitab to help us track and analyze the productivity of our employees, and we even have ideas for projects to improve processes at our corporate office."


Skills of Central Pennsylvania


  • Nonprofit organization assisting individuals with disabilities in acquiring employment
  • Founded in 1960
  • Serves 16 Pennsylvania counties
  • Provides a skilled workforce of over 300 employees


Decrease costs associated with receiving defective units from a supplier


Minitab® Statistical Software


  • Saved its manufacturer from paying for defective supplier units
  • Improved the overall quality of processes internally and externally
  • Launched several projects as a result