Challenge 21.1

Challenge 21.1 – Predicting 1xR


TracFone’s customers draw from diverse and vibrant backgrounds. For example, they may be proudly pragmatic who appreciate good value mobile service plans. Alternatively, they may be travelers that are temporarily visiting friends or family or forming new memories on their vacation to take home with them. They may even belong to financially fragile communities that have traditionally been underserved by the large wireless providers that required credit checks and long-term contracts. Ever since our inception in 1996, our focus has always been on providing Coverage And Access For All

In the prepaid cellular service market that we pioneered in the USA, customers pay for service in advance of the month with no contracts or obligations to continue their service the following month. This gives our customers tremendous flexibility to manage their monthly spending and adapt to their shifting circumstances. They may continue to prepay the same amount for next month’s service, change to a different service plan, or let their service go inactive.


The 21.1 challenge is to use machine learning to predict one-time-redeemers (1xR). A 1xR is a customer that makes only a single redemption (i.e. stays with only one month) and then goes inactive.

A customer going inactive may be expected for a tourist temporarily visiting the USA. Meanwhile, financially fragile members of our community may become inactive for the month and later return with the necessary funds to activate their service. In some circumstances, a customer may not be happy with their service, their plan or sees opportunities for us to do better. If we can accurately predict a new customer’s likelihood to be a 1xR, it would enable us to understand their underlying intent and deliver services specific to their needs proactively.


1st place – Group 6

2nd place – Group 15

3rd place – Group 9


Who can join in?

TracHack 21.1 participants will be students enrolled in the Master of Science in Business Analytics (MSBA) in A/Prof Daniel McGibney’s class.

When & where?

TracHack 21.1 is an online competition. The data for the competition is released April 5, 2021 and ends April 25, 2021 at 11:59 pm US Eastern Time.

How are the winners selected?

Teams are welcome to make as many submissions along the way, and the accuracy of solution will be evaluated based on F1 score. The winners of the challenge will be announced based on the ranking from the final submission. That means your team needs to ensure your final submission is the best solution that you come up with during the three-week period.

The top three teams with the highest F1 score will win cash prizes, fame and glory. Even though the final ranking is based on the final submission, it is a good idea to validate the approach and solution along the way using regular submissions as checkpoints.

What technologies can I use?

TracHack 21.1 solutions must be built using PySpark. TracFone will provide a dedicated environment with PySpark and Jupyter, dedicated for each team. Teams will access data, build their solutions and submit their predictions via that dedicated environment. So it is important for you to get familiar with it and set it up once your team signs up and gets the relevant details. Keep in mind that the winning teams will have to submit the code that produced their winning solution once the winners are announced for verification prior to the awards.

Where is the data?

The data will be released on April 5 accessible from within that environment. Teams may not download part or all of the data locally. Teams downloading the data outside that environment will be disqualified from the competition. All data and code developed by the teams must remain in the team’s environment.

How do I submit my solution?

The details are available on the submissions page and consult the FAQ page.

What happens when my team wins?

You win fame, glory and bragging rights. There are also cash prizes for the teams to go with trophies:

1st place team: $3,000

2nd place team: $2,000

3rd place team: $1,000

The winning teams will be required to make a 5-minute presentation at the award ceremony on April 30 that describes their solution and how they tackled this problem.

How do I get started?

  • Understand the Rules and consult the FAQ.
  • Join a team (if not already) – Check with A/Prof Daniel McGibney.
  • Sign an NDA on data usage – If you are part of a signed up team you would have gotten a DocuSign email.
  • Ensure your are set up to access your team’s dedicated PySpark development environment. – Check your emails for setup and login instructions once you have signed the NDA.
  • Set up to make your Submissions.

Key dates

March 22, 2021TracHack 21.1 Problem Announced
April 5, 2021TracHack 21.1 Data Released
April 25, 2021 – 11:59pm US ETDeadline for Final Submission
April 28, 2021 – 3:30pm US ETAwards & Presentations


If you have any questions, feel free to reach out to us at Once your team is registered you’ll be invited to a Microsoft Teams Channel.