7/2/18 7/2/18

How to Ace the In-Person Data Science Interview

I’ve written previously about my recent data science job hunt, but this article is solely devoted to the in-person interview. That full-day, try to razzle-dazzle em’, cross your fingers and hope you’re well prepared for what gets thrown at you. After attending a ton of these interviews, I’ve found that they tend to follow some pretty standard schedules.

But first, if your sending out job applications and aren't hearing back, you'll want to take a second look at your resume. I've written a couple articles on how to create a strong resume. One helpful article is

here.

You may meet with 3–7 different people, and throughout the span of meeting with these different people, you’ll probably cover:

Tell me about yourself
Behavioral interview questions
“White boarding” SQL
“White boarding” code (technical interview)
Talking about items on your resume
Simple analysis interview questions
Asking questions of your own

Tell me about yourselfI’ve mentioned this before when talking about phone screens. The way I approach this never changes. People just want to hear that you can speak to who you are and what you’re doing. Mine was some variation of:I am a Data Scientist with 8 years of experience using statistical methods and analysis to solve business problems across various industries. I’m skilled in SQL, model building in R, and I’m currently learning Python.

Behavioral Questions

Almost every company I spoke with asked interview questions that should be answered in the STAR format. The most prevalent STAR questions I’ve seen in Data Science interviews are:

Tell me about a time you explained technical results to a non-technical person
Tell me about a time you improved a process
Tell me about a time with a difficult stakeholder, and how was it resolved

The goal here is to concisely and clearly explain the Situation, Task, Action and Result. My response to the “technical results” questions would go something like this:Vistaprint is a company that sells marketing materials for small businesses online (always give context, the interviewer may not be familiar with the company). I had the opportunity to do a customer behavioral segmentation using k-means. This involved creating 54 variables, standardizing the data, plenty of analysis, etc. When it was time to share my results with stakeholders, I had really taken this information up a level and built out the story. Instead of talking about the methodology, I spoke to who the customer segments were and how their behaviors were different. I also stressed that this segmentation was actionable! We could identify these customers in our database, develop campaigns to target them, and I gave examples of specific campaigns we might try. This is an example of when I explained technical results to non-technical stakeholders. (always restate the question afterwards).For me, these questions required some preparation time. I gave some real thought to my best examples from my experience, and practiced saying the answer. This time paid-off. I was asked these same questions over and over throughout my interviewing.

White Boarding:

White Boarding SQL

This is when the interviewer has you stand at the whiteboard an answer some SQL questions. In most scenarios, they’ll tape a couple pieces of paper up on the whiteboard. I have a free video course on refreshing SQL for the data science interview

here.

White Boarding Code

As mentioned in my previous article. I was asked FizzBuzz two days in a row by two different companies. A possible way to write the solution (just took a screenshot of my computer) is below:

The coding problem will most likely involve some loops, logic statements and may have you define a function. The hiring manager just wants to be sure that when you say you can code, you at least have some basic programming knowledge.

Items on Your Resume

I’ve been asked about all the methods I mention on my resume at one point or another (regression, classification, time-series analysis, MVT testing, etc). I don’t mention my thesis from my Master’s Degree on my resume, but casually referenced it when asked if I had previously had experience with Bayesian methods.

The interviewer followed up with a question on the prior distributions used in my thesis.

I had finished my thesis 9 years ago, couldn’t remember the priors and told him I’d need to follow up.

I did follow up and send him the answer to his question, they did offer me a job, but it’s not a scenario you want to find yourself in. If you are going to reference something, be able to speak to it. Even if it means refreshing your memory by looking at wikipedia ahead of the interview. Things on your resume and projects you mention should be a home run.

Simple Analysis Questions

Some basic questions will be asked to make sure that you have an understanding of how numbers work. The question may require you to draw a graph or use some algebra to get at an answer, and it’ll show that you have some business context and can explain what is going on. Questions around changes in conversion, average sale price, why is revenue down in this scenario? What model would you choose in this scenario? Typically I’m asked two or three questions of this type.

I was asked a probability question at one interview. They asked what the expected value was of rolling a fair die. I was then asked if the die was weighted in a certain way, what would the expected value of that die be. I wasn’t allowed to use a calculator.

Questions I asked:

Tell me about the behaviors of a person that you would consider a high-performing/high-potential employee.

Honestly, I used the question above to try and get at whether you needed to work 60 hours a week and work on the weekends to be someone who stood out. I pretty frequently work on the weekends because I enjoy what I do, I wouldn’t enjoy it if it was expected.

What software are you using?

Really, I like to get this question out of the way during the phone screen. I’m not personally interested in working for a SAS shop, so I’d want to know that upfront. My favorite response to this question is “you can use whatever open source tools you’d like as long as it’s appropriate for the problem.”

Is there anything else I can tell you about my skills and qualifications to let you know that I am a good fit for this job?

This is your opportunity to let them tell you if there is anything that you haven’t covered yet, or that they might be concerned about. You don’t want to leave an interview with them feeling like they didn’t get EVERYTHING they needed to make a decision on whether or not to hire you.

When can I expect to hear from you?

I also ask about the reporting structure, and I certainly ask about what type of projects I’d be working on soon after starting (if that is not already clear).

Summary

I wish you so much success in your data science interviews. Hopefully you meet a lot of great people, and have a positive experience. After each interview, remember to send your thank you notes! If you do not receive an offer, or do not accept an offer from a given company, still go on LinkedIn and send them connection requests. You never know when timing might be better in the future and your paths might cross.

To read about my job hunt from the first application until I accepted an offer,

click here

How to ace the data science in-person interview. Data analysis, data collection , data management, data tracking, data scientist, data science, big data, data design, data analytics, behavior data collection, behavior data, data recovery, data analyst. For more on data science, visit www.datamovesme.com.

7/2/18 7/2/18

The Successful Data Science Job Hunt

The point of this article is to show you what a successful Data Science job hunt looks like, from beginning to end. Strap-in, friends. I’m about to bring you from day 1 of being laid-off to the day that I accepted an offer. Seriously, it was an intense two months.I have an MS in Statistics and have been working in Advanced Analytics since 2010. If you’re new to the field, your experience may be different, but hopefully you’ll be able to leverage a good amount of this content.We’re going to cover how I leveraged LinkedIn, keeping track of all the applications, continuing to advance your skills while searching, what to do when you receive an offer, and how to negotiate.

Day 1 Being Laid-off

dyed my hair bright pink before job hunting

Vistaprint decided to decrease it’s employee headcount by $20 million dollars in employee salary, I was part of that cut. I was aware that the market was hot at the moment, so I was optimistic from day 1. I received severance, and this was an opportunity to give some real thought about what I would like my next move to be.I happened to get laid-off 4 days after I had just dyed my hair bright pink for the first time, that was a bummer.I actually went to one job interview with my pink hair, and they loved it. However, I did decide to bring my hair back to a natural color for the rest of my search.

Very First Thing I Did:

I am approached by recruiters pretty frequently on LinkedIn. I always reply.Although if you’re just getting into the field, you may not have past messages from recruiters in your LinkedIn mail, but I mention this so that you can start to do this throughout the rest of your career.Now that I was looking, my first action was to go through that list, message everyone and say:“Hi (recruiter person), I’m currently looking for a new opportunity. If there are any roles you’re looking to fill that would be a good fit, I’d be open to a chat.”

There were a number of people that replied back saying they had a role, but after speaking with them, it didn’t seem like the perfect fit for me at the moment.In addition to reaching out to the recruiters who had contacted me, I also did a google search (and a LinkedIn hunt) to find recruiters in the analytics space. I reached out to them as well to let them know I was looking. You never know who might know of something that isn’t on the job boards yet, but is coming on soon.

First Meeting With the Career Coach

As part of the layoff, Vistaprint set me up with a career coach. The information she taught me was incredibly valuable, I’ll be using her tips throughout my career. I met with Joan Blake from Transition Solutions. On our first meeting, I brought my resume and we talked about what I was looking for in my next role.Because my resume and LinkedIn had success in the past, she did not change much of the content on my resume, but we did bring my skills and experience up to the top, and put my education at the bottom.

They also formatted it to fit on one page. It’s starting to get longer, but I’m a believer in the one page resume.I also made sure to include a cover letter with my application. This gave me the opportunity to explicitly call out that my qualifications are a great match with their job description. It’s much more clear than having to read through my resume for buzzwords.I kept a spreadsheet with all of the companies I applied to. In this spreadsheet I’d put information like the company name, date that I completed the application, if I had heard back, the last update, if I had sent a thank you, the name of the hiring manager, etc.This helped me keep track of all the different things I had in flight, and if there was anything I could be doing on my side to keep the process moving.

Each Application:

For each job I applied to, I would then start a little hunt on LinkedIn. I’d look to see if anyone in my network currently worked for the company. If so, they’d probably like to know that I’m applying, because a lot of companies offer referral bonuses. I’d message the person and say something like:Hey Michelle,I’m applying for the Data Scientist position at ______________. Any chance you’d be willing to refer me?

If there is no one in my network that works for the company, I then try and find the hiring manager for the position. Odds are it was going to be a title like “Director (or VP) of Data Science and Analytics”, or some variation, you’re trying to find someone who is a decision maker.This requires LinkedIn Premium, because I’m about to send an InMail. My message to a hiring manager/decision maker would look something like:

Hi Sean,I’m interested in the remote Data Science position, and I’m hoping I can get my resume in the right hands. I have an MS in Statistics, plus 7 years of real-world experience building models. I’m a wiz at SQL, modeling in R, and I have some exposure to Python.I’d appreciate the opportunity to speak with the appropriate person about the open position, and share how I’ve delivered insights and added value for company’s through the use of statistical methods.Thanks, Kristen

Most people actually responded, Joan (the career coach) was surprised when I told her about my cold-calling LinkedIn success.

I Started Applying to Jobs, and Started Having “Phone Screens”

Phone screens are basically all the same. Some were a little more intense and longer than others, but they were all around a half hour, and they’re typically with someone in HR. Since it’s HR, you don’t want to go too deep in the technical stuff, you just want to be able to pass this stage, follow up with a note thanking them for their time, and try to firm up when you’ll be able to speak with the hiring manager :)Tell me about yourself:People just want to hear that you can speak to who you are and what you’re doing.

Mine was some variation of:

I am a Data Scientist with 7 years of experience using statistical methods and analysis to solve business problems across various industries. I’m skilled in SQL, model building in R, and I’m currently learning Python.

What are you looking to do?I’d make sure that what I’m looking to do ties directly to the job description. At the end of the day, it was some variation of:

“I’m looking to continuously learn new tools, technologies and techniques. I want to work on interesting problems that add business value”.

Then I’d talk about how interesting one of the projects on the job description sounded.What are you looking for in terms of salary?Avoid this question if you can, you’ll be asked, but try to steer in a different direction. You can always reply with “I’ve always been paid fairly in the past, I trust that I’ll be paid fairly working for [insert company name]. Do you have an idea of the salary range for the position”.They’ll know the range for the position, but they’ll probably tell you that they don’t. Most of the time I’d finally concede and give them my salary, this doesn’t mean that you won’t be able to negotiate when you receive an offer.

All The While, I’m Still Learning, And Can Speak to This in Interviews:

If I was going to tell everyone that I was very into learning technologies, I better be “walking the walk” so to speak. Although I am constantly learning, because it’s in my nature. Make sure that if you say you’re learning something new, you’re actually studying it.

The course I took was: Python for everybody

Disclaimer: This is an affiliate link, meaning that at no cost to you, I will earn a commission if you end up signing up for this course.

This course goes over your basic lists, arrays, tuples, defining a function.. but it also goes over how to access and parse web data. I had always wanted to know how to access Twitter data for future analysis, so this was super cool. The specialization (that’s the name they give for a series of courses on Coursera) also gives a brief overview in how to construct a database. This was a super bonus for me, because if I want to operationalize a model, I’m going to want to know how to write from Python to a database table. All-in-all, I found this course to be a great use of my time, and I finished it being able to speak to things intelligently, that I was not able to speak to prior to taking the course.

In Person Interviews:

I've written a whole article on in person interviews: here

At some point, you might receive a call saying they plan on putting an offer together for you, if you're still interested.Great! You’ve got an offer coming. At this point, you want to call all the other companies that you would consider an offer from and say “I’ve been informed that I am expecting an offer, is there anything you can do to accelerate your process?”I mentioned this to 2 companies. One of them did speed up their process and it resulted in an additional offer. The other company said that they would not speed up their process, I thanked them for their time and said I'd hope to cross paths in the future.

Negotiating:

The phone rings, and you answer. This is it, you’re getting your first offer. It’s time to negotiate. Only a relatively small percentage of people ever negotiate their salary, the percentage is even smaller when we’re talking about women.Ladies! Negotiate! I’m here rooting for you, you got this.Joan from Transition Solutions had coached me on this. She said “Don’t try and solve the problem for them”.When they call, let them know how excited you are that they called, and that you’re interested in hearing their offer.

Once you’ve heard the salary, vacation time, and that they’re going to send over the benefits information, you can say something along the lines of:

"Thank you so much for the offer, I really appreciate it. You know, I was hoping that you could do more on the salary."

Then wait for a response, and again be positive. They’ll most likely say that they need to bring this information back to the hiring manager."

Great! I look forward to hearing back from you. I’ll take some time to look over the benefits package. Want to speak again on ____. I’m feeling confident that we can close this."

Then you’d be walking away from the conversation with a concrete time that you’ll speak to them next, and you let them know that you were happy to hear from them, all of this is positive!I successfully negotiated my offer, and started a week later. I couldn’t be happier with where I am now and the work I’m doing. It took a lot of applying and a lot of speaking with companies who weren’t “the one”, but it was worth it.To sum up my job search. I learned that a targeted cover letter and directly applying on a company website greatly increase the response rate on your applications.

I learned that you can effectively leverage LinkedIn to find the decision maker for a position and they’ll help keep the process moving if you’re a good fit. I also gained a ton of confidence in my ability to articulate my skills, and this came with practice. I wish you lots of success on your hunt, and I hope that there was a couple of tips in this article that you are able to use :)