Red flags as Data Hiring Manager

4 min readApr 5, 2022


A short story about the red flags I have learned during the last years as a hiring manager

Hiring is the most critical function of a manager and leader. Hire the right people to make your job easier. I have decided to compile some of the traits I have been avoiding hiring.

No in-role promotion or growth within the company

Once you start being more senior, with around 7 to 10 years of experience post-graduation, you start being considered for a manager or leading technical roles.

Having hired some seniors and some managers and talking to other leaders in the organization, I see that job-hopping is pretty much accepted in Tech. It is true … to a certain extent when it becomes a red flag. The red flag comes from the lack of internal promotion but only external promotion (upon hiring). Let’s take an example:

2011–2012 → Finance analyst at MNC

2012–2014 → Manager business insight, small tech firm

2015–2017 → BI lead, startup

2017–2019 → BI lead, tech scaleup

2019–2021 → BI manager, scaleup

2021– onward→ BI manager, large tech

Every company is a 1 to 2 year of experience. Zero promotion was internal. This is a red flag when hiring senior people. While it is true that internal promotions are difficult to obtain and could be biased, it cannot be the case at 6 different firms. Now consider the following CV:

2011–2012 → Finance analyst at MNC

2012–2014 → Finance manager at the same MNC

2015–2015 → BI lead, startup, 6 months

2015–2017 → BI analyst, tech scaleup

2017–2019 → BI lead, same tech scaleup

2019–2021 → BI manager, same tech scaleup

2021– onward→ BI manager, large tech

The 2 CVs end at the same level and company. I claim the second cv is much more attractive than the first one and will pass the screening. The second CV experienced 4 companies spanning 10 years but this is perfectly fine.

My advice → It is okay to leave a job after 6 months if you think it is not a right fit, it is okay to reach 30 years old with 4–6 companies on your CV but some of this experience much demonstrate career progression and trust from your leaders and peers. You can fake it for 1 year, you cannot fake it for 4 years and get promoted.

Unrealistic job description

I have seen this type of description of the experience:

6 months of experience at a tech company [Real example]:

  • Developed recommendation system leading to a 15% uplift
  • Developed NLP chatbot for care support leading to a 20% reduction in manual effort
  • Revamp a global search engine yielding to 30% improvement

While it is not possible to have been involved in such projects over time. It is unlikely that if it was done in such a short period of time that you were the main actor of the project or that this is your direct contribution. Hiring managers acknowledge that work is done as part of a team, do try to extract your own impact, and do not make it unrealistic. Do note that if you use “developed” the manager will most likely assume that you have built and implemented the model, DS + ML.

Stick to your position during the Interview

This one is quite obvious. Some parts of the interview are about problem-solving. There are many solutions available and none is perfect. Therefore whatever you suggest, the interviewer may challenge you to understand how you are reacting to feedback. Sticking to your position without good argumentation is not acceptable. Open up, and consider pros and cons of your solution.

Explain having done state of the art DS/ML but cannot grasp gradient descent well

An interview will rarely test state-of-the-art modeling and machine learning. Most questions are more limited in technical difficulty so get to know the basics of:

Gradient descent, Linear regression and variant, trees methods, random forest, data leakage, xgboost, cost functions, Bayesian statistics…

before diving into LSTM, RNN, Autoencoders, and other fancier solutions.

Read the screen

Covid life, most interviews are remote and conducted via zoom. While it is not reliable for the interviewer to ask “Textbook” questions they may be useful to understand the thought process or lead to another question. Think that reading on the screen or typing will lead to rejection. Sadly, I rejected more candidates for this reason than I hired last year while the questions were not textbook questions.

Do not read, all candidates I hired said “I don’t know” to one question.




Strategy/Data/Leadership head of DS at OCBC ~~ exTwitter ~~ ex-gojek