RMB Monthly Mini Challenge #1: Nowcast April
Can you nowcast South Africa’s April CPI?
$600 USD
~1 month to go
33 active · 317 enrolled
South Africa
Financial Services

This is the first of five RMB Monthly Mini Challenges. In order to participate in the main RMB CPI Nowcasting Challenge which starts in September 2023, you need to participate in at least 3 out of the 5 Monthly Mini Challenges.

Join RMB and Zindi in revolutionizing the world of finance by predicting South Africa's inflation with CPI as a proxy, using alternative data in cutting-edge machine-learning models.

Inflation is a fundamental component of understanding how an economy works. If we think through the acronym, CPI stands for consumer price index. It has a bearing on household’s purchasing power and influences decisions on whether we can spend or save.

Based on the prices of a set basket of goods and services which are regularly bought, an overall price level is determined. In South Africa, this basket comprises of 412 items grouped into 12 categories and is surveyed monthly by Statistics South Africa, which assigns a weighting to each of the items to make up 100% of the basket. Comparing the changes in prices month-to-month and year-on-year tells us how much prices rise or fall over a given period. It is a generalized measure and we’re made aware of the changes through monthly publications by Stats SA.

Nowcasting CPI is an important indicator for banks and their clients as it provides insight into rate hikes/reductions which are influenced by inflation. Existing CPI prediction methods have generally focused on time series forecasting as well analysing economic data, such as GDP, and unemployment rates. Nowcasting is a modern approach to help monitor economic activity in the near future.

In this challenge, you will be provided with historical CPI data, air quality data from Sentinel-5P, as well as trade data from various sources.

Please note that these data sources are just a starting point to use as inputs to any model you may be building. Feel free to look for alternative sources outside of the starting list. The only prerequisites for using other data sources, is that data should be freely available to all participants (no paid licensed data) and the data will need to be emailed to Zindi who will work with RMB to approve it for use in the challenge. If you find additional data that you believe could be of use, please submit the dataset via this FORM to confirm whether it can be used, and it will be added to the challenge.

Your task is to nowcast the next CPI value as well as CPI sub-categories for the month of April, using data up until 30 April 2023.

This is the first Mini Challenge that contributes towards qualifying for the RMB CPI Nowcasting Challenge.

About RMB

We are a leading African Corporate and Investment Bank and part of one of the largest financial services groups (by market capitalisation) in Africa – FirstRand Limited.

We are passionate Solutionists who offer our clients innovative, advisory, funding, trading, corporate banking, principal investing and private banking solutions. We are innovative thinkers who turn challenges into opportunities to deliver on Traditional values. Innovative ideas.


The error metric for this competition is the Root Mean Squared Error.

This challenge will be evaluated on a rolling leaderboard.

You are required to Nowcast the April CPI headline value as well as 12 sub-categories (unweighted). The 12 sub-categories are food and non-alcoholic beverages, alcoholic beverages and tobacco, clothing and footwear, housing and utilities, household contents and services, health, transport, communication, recreation and culture, education, restaurants and hotels, miscellaneous goods and services.

The Public leaderboard involves your solutions being scored against the RMB In-House Data Team Predictions for April. Please note that your solution being lower on the public leaderboard does not necessarily mean your predictions are poor. It just means that your predictions are different from the RMB team’s expectations. While the public leaderboard can be helpful in sense-checking your solution, what is more important is the final scoring of the leaderboard which occurs after Stats SA releases the official numbers on the 10th of May.

The private leaderboard will be revealed on 13 May, these values will be the actual CPI values that were released on 10 May 2023.

The SampleSubmission for this challenge looks like:

ID                          		   Value
April_headline CPI                         107.8
April_food and non-alcoholic beverages     115.2
April_alcoholic beverages and tobacco      107.2
April_clothing and footwear                103.6
April_housing and utilities                104.8
April_household contents and services      107.3
April_health                               105.6
April_transport                            110.7
April_communication                        100.1
April_recreation and culture               104.1
April_education                            105.1
April_restaurants and hotels               107.5
April_miscellaneous goods and services     106.1

1st place: $300 USD

2nd place: $200 USD

3rd place: $100 USD


This challenge starts on 21 March 2023. The datasets and submissions will be available at this time. This challenge is 2 weeks longer than the other mini challenges.

Submission for April CPI must be submitted by 1 May 2023 at 23:59 GMT.

If you would like to use an additional dataset, please submit your dataset to this form by 10 April 2023 and it will be added to the challenge by 17 April 2023.

Final scoring of the leaderboard will be released soon after Stats SA release the April CPI values.

We reserve the right to update the contest timeline if necessary.

How to get started with Zindi

How to enroll in your first Zindi competition

How to create a team on Zindi

How to update your profile on Zindi


This challenge is open to all.

Teams and collaboration

You may participate in competitions as an individual or in a team of up to four people. When creating a team, the team must have a total submission count less than or equal to the maximum allowable submissions as of the formation date. A team will be allowed the maximum number of submissions for the competition, minus the total number of submissions among team members at team formation. Prizes are transferred only to the individual players or to the team leader.

Multiple accounts per user are not permitted, and neither is collaboration or membership across multiple teams. Individuals and their submissions originating from multiple accounts will be immediately disqualified from the platform.

Code must not be shared privately outside of a team. Any code that is shared, must be made available to all competition participants through the platform. (i.e. on the discussion boards).

The Zindi data scientist who sets up a team is the default Team Leader but they can transfer leadership to another data scientist on the team. The Team Leader can invite other data scientists to their team. Invited data scientists can accept or reject invitations. Until a second data scientist accepts an invitation to join a team, the data scientist who initiated a team remains an individual on the leaderboard. No additional members may be added to teams within the final 5 days of the competition or last hour of a hackathon.

The team leader can initiate a merge with another team. Only the team leader of the second team can accept the invite. The default team leader is the leader from the team who initiated the invite. Teams can only merge if the total number of members is less than or equal to the maximum team size of the competition.

A team can be disbanded if it has not yet made a submission. Once a submission is made individual members cannot leave the team.

All members in the team receive points associated with their ranking in the competition and there is no split or division of the points between team members.

Datasets and packages

The solution must use publicly-available, open-source packages only.

You may use only the datasets provided for this competition. Automated machine learning tools such as automl are not permitted.

You may use pretrained models as long as they are openly available to everyone.

The data used in this competition is the sole property of Zindi and the competition host. You may not transmit, duplicate, publish, redistribute or otherwise provide or make available any competition data to any party not participating in the Competition (this includes uploading the data to any public site such as Kaggle or GitHub). You may upload, store and work with the data on any cloud platform such as Google Colab, AWS or similar, as long as 1) the data remains private and 2) doing so does not contravene Zindi’s rules of use.

You must notify Zindi immediately upon learning of any unauthorised transmission of or unauthorised access to the competition data, and work with Zindi to rectify any unauthorised transmission or access.

Your solution must not infringe the rights of any third party and you must be legally entitled to assign ownership of all rights of copyright in and to the winning solution code to Zindi.

Submissions and winning

You may make a maximum of 5 submissions per day.

You may make a maximum of 200 submissions for this competition.

Before the end of the competition you need to choose 2 submissions to be judged on for the private leaderboard. If you do not make a selection your 2 best public leaderboard submissions will be used to score on the private leaderboard.

During the competition, your best public score will be displayed regardless of the submissions you have selected. When the competition closes your best private score out of the 2 selected submissions will be displayed.

Zindi maintains a public leaderboard and a private leaderboard for each competition.

The public leaderboard involves your solutions being scored against the RMB In-House Data Team Predictions for April. Please note that your solution being lower on the public leaderboard does not necessarily mean your predictions are poor. It just means that your predictions are different from the RMB team’s expectations. While the public leaderboard can be helpful in sense-checking your solution, what is more important is the final scoring of the leaderboard which occurs after Stats SA releases the official numbers on the 10th of May.

While the competition is open, the public leaderboard will rank the submitted solutions by the accuracy score they achieve. Upon close of the competition and release of the April CPI values, the private leaderboard, which covers April CPI values, will be made public and will constitute the final ranking for the competition.

Note that to count, your submission must first pass processing. If your submission fails during the processing step, it will not be counted and not receive a score; nor will it count against your daily submission limit. If you encounter problems with your submission file, your best course of action is to ask for advice on the Competition’s discussion forum.

If you are in the top 10 at the time the leaderboard closes, we will email you to request your code. On receipt of email, you will have 48 hours to respond and submit your code following the Reproducibility of submitted code guidelines detailed below. Failure to respond will result in disqualification.

To be eligible for cash prizes, 1st, 2nd, or 3rd on the final leaderboard will release their top solutions under an open source license for ongoing use and learning.

If two solutions earn identical scores on the leaderboard, the tiebreaker will be the date and time in which the submission was made (the earlier solution will win).

The winners will be paid via bank transfer, PayPal, or other international money transfer platform. International transfer fees will be deducted from the total prize amount, unless the prize money is under $500, in which case the international transfer fees will be covered by Zindi. In all cases, the winners are responsible for any other fees applied by their own bank or other institution for receiving the prize money. All taxes imposed on prizes are the sole responsibility of the winners. The top 3 winners or team leaders will be required to present Zindi with proof of identification, proof of residence and a letter from your bank confirming your banking details.Winners will be paid in USD or the currency of the competition. If your account cannot receive US Dollars or the currency of the competition then your bank will need to provide proof of this and Zindi will try to accommodate this.

Payment will be made after code review and sealing the leaderboard.

You acknowledge and agree that Zindi may, without any obligation to do so, remove or disqualify an individual, team, or account if Zindi believes that such individual, team, or account is in violation of these rules. Entry into this competition constitutes your acceptance of these official competition rules.

Zindi is committed to providing solutions of value to our clients and partners. To this end, we reserve the right to disqualify your submission on the grounds of usability or value. This includes but is not limited to the use of data leaks or any other practices that we deem to compromise the inherent value of your solution.

Zindi also reserves the right to disqualify you and/or your submissions from any competition if we believe that you violated the rules or violated the spirit of the competition or the platform in any other way. The disqualifications are irrespective of your position on the leaderboard and completely at the discretion of Zindi.

Please refer to the FAQs and Terms of Use for additional rules that may apply to this competition. We reserve the right to update these rules at any time.

Reproducibility of submitted code

  • If your submitted code does not reproduce your score on the leaderboard, we reserve the right to adjust your rank to the score generated by the code you submitted.
  • If your code does not run you will be dropped from the top 10. Please make sure your code runs before submitting your solution.
  • Always set the seed. Rerunning your model should always place you at the same position on the leaderboard. When running your solution, if randomness shifts you down the leaderboard we reserve the right to adjust your rank to the closest score that your submission reproduces.
  • Custom packages in your submission notebook will not be accepted.
  • You may only use tools available to everyone i.e. no paid services or free trials that require a credit card.


A README markdown file is required

It should cover:

  • How to set up folders and where each file is saved
  • Order in which to run code
  • Explanations of features used
  • Environment for the code to be run (conda environment.yml file or an environment.txt file)
  • Hardware needed (e.g. Google Colab or the specifications of your local machine)
  • Expected run time for each notebook. This will be useful to the review team for time and resource allocation.

Your code needs to run properly, code reviewers do not have time to debug code. If code does not run easily you will be bumped down the leaderboard.

Consequences of breaking any rules of the competition or submission guidelines:

  • First offence: No prizes for 6 months and 2000 points will be removed from your profile (probation period). If you are caught cheating, all individuals involved in cheating will be disqualified from the challenge(s) you were caught in and you will be disqualified from winning any competitions for the next six months and 2000 points will be removed from your profile. If you have less than 2000 points to your profile your points will be set to 0.
  • Second offence: Banned from the platform. If you are caught for a second time your Zindi account will be disabled and you will be disqualified from winning any competitions or Zindi points using any other account.
  • Teams with individuals who are caught cheating will not be eligible to win prizes or points in the competition in which the cheating occurred, regardless of the individuals’ knowledge of or participation in the offence.
  • Teams with individuals who have previously committed an offence will not be eligible for any prizes for any competitions during the 6-month probation period.

Monitoring of submissions

  • We will review the top 10 solutions of every competition when the competition ends.
  • We reserve the right to request code from any user at any time during a challenge. You will have 24 hours to submit your code following the rules for code review (see above). Zindi reserves the right not to explain our reasons for requesting code. If you do not submit your code within 24 hours you will be disqualified from winning any competitions or Zindi points for the next six months. If you fall under suspicion again and your code is requested and you fail to submit your code within 24 hours, your Zindi account will be disabled and you will be disqualified from winning any competitions or Zindi points with any other account.