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Data Science Specialization: What's the Value?

By the first or second week into R Programming, students in the Johns Hopkins Data Science Specialization often express frustration about the degree to which they have to figure things out on their own in order to complete quizzes and course assignments. This frustration usually comes in the form of forum posts, many of which generate large volumes of "me too" replies.

Value of the Specialization

One of the major components of the Data Science Specialization is the hacker mentality described in the Data Scientist's Toolbox. The Specialization classes are highly condensed versions of Johns Hopkins classes that cost $3,310 USD each (as of fall 2016).

In my view, here's what a student gets for the $49 USD (as of January 2017) for one course:

  • A set of lectures that describe the topic, about 45 - 60 minutes per week (except for the Capstone, where the lectures are 1 - 3 minutes per week due to the fact that it is the ultimate embodiment of the hacker mentality),

  • A set of slides accompanying the lectures that students can use for reference,

  • Guidance on how to leverage outside resources to learn things that aren't directly taught in the course,

  • A set of exercises that push students to figure out how to do things of practical value to a data scientist, beyond "trivial" examples,

  • A set of quizzes that require students to use what has been covered in the lectures to confirm understanding of the material, and function as a sandbox where they can solve problems and determine that the answers are correct without being corrected by observers on the internet or supervisors,

  • A set of course projects that challenge students to produce legitimate work products that can be showcased in a portfolio, and

  • Access to a community of students, mentors, and high quality community-generated content that provides context beyond what is covered in the lectures, built by people who have already taken the Specialization courses, some of whom are practicing data scientists or who manage teams of data scientists.

The bottom line is that the Data Science Specialization provides access to content from a prestigious U.S. university at a very affordable price, even if there is significantly less personal attention than is typical for a graduate level course in meat space at a university.

Furthermore, since the Specialization uses the open source language R, students also learn how to use very sophisticated statistics software at a fraction of the cost of commercial statistics packages, as I discuss in Commercial Statistics Packages: An Historical Perspective.

"Difficulty" is Relative to One's Experience

Students new to data science sometimes lack perspective of the challenges in learning one statistics language versus another. The Specialization attracts many students who may have had one or more undergraduate or graduate statistics courses, including exposure to statistics software such as SPSS or SAS. Usually the programming problems in these courses are very easy, leading students to three problems when they start the Data Science Specialization:

  1. An over-optimistic sense of one's skill level in a statistics language,

  2. An unrealistic expectation that R should work like the statistics language the student previously learned, and

  3. Frustration that R is much more difficult than the language they learned in statistics class.

Helping students overcome these frustrations requires exposure to additional information to provide context against which their experiences can be compared. I have written a few articles to address these issues, including:

  • Thinking in R versus Thinking in SAS, which illustrates how one's exposure to a statistics package affects how s/he thinks about solving problems, contrasting SAS and R.

  • Why is R Harder than SAS explains why students with a SAS backround perceive R to be significantly more difficult than SAS.

  • A SAS Version of pollutantmean() addresses the relative complexity of SAS versus R on an equal task -- implementation of the R Programming pollutantmean() function.

Why Emphasize the Hacker Mentality?

The early courses in the Data Science Specialization repeatedly encourage students to cultivate the hacker mentality. That is, students are expected to learn things that are not directly taught in the lectures, readings, and swirl() exercises. They are also expected to figure a number of things out on their own, using publicly available resources ranging from Google to Stackoverflow, CrossValidated and the wide variety of books and references related to R Programming.

For example, the R Programming lexical scoping assignment can be completed with 3 changes in the example cachemean.R program, one of which is a global find / replace on the string mean, plus a couple of comment lines. Done this way, a student can get a perfect score on the assignment without actually learning how lexical scoping works. Extra work is required to fully comprehend what's going on in the sample code, as I describe in Demystifying makeVector().

Many students express frustration about this requirement when they struggle to complete the first few courses in the Specialization without understanding that it is actually a test of students' tenacity. To succeed in this field, one has to have a high level of ingenuity and creativity. One must also have an unwillingness to give up in the face of ambiguous problems. Challenging students to develop these characteristics at the start of the Specialization by forcing them to find and use relevant resources outside the lectures makes them a habit by the time students take the statistics courses, including Statistical Inference, Regression Models, Practical Machine Learning, and the Capstone.

You: The Final Ingredient

The Specialization courses provide everything one needs to direct one's learning in data science at an affordable price. The final ingredient is the student's motivation and determination to solve problems. Yes, the introductory assignments in R Programming are a big jump in difficulty from the lectures. Yes, the course projects for Getting and Cleaning Data, Reproducible Research, and Practical Machine Learning are very challenging. Yes, the mathematics in Statistical Inference and Regression Models are tough for students who haven't previously studied statistics. Yes, the course projects for Reproducible Research, Practical Machine Learning, and the Capstone stress the limits of old, low memory computer equipment.

On the other hand, the Specialization presents an opportunity for students to produce some outstanding quality deliverables for their portfolios, solving challenging problems that relate well to real world work in data science.

After all, that's what Data Science in real life is all about: ambiguous problems, messy data, scores of algorithms to consider, and limited computer resources that challenge the Data Scientist to produce actionable results within an acceptable cost structure. By the end of the Specialization a student has figured out how to learn about a tough topic, developed a level of self-sufficiency to tackle ambiguous problems, and produced deliverables that are worthy of sharing with potential employers for entry level data science jobs.

What Type of Job Can I Expect After Completing the Specialization?

The Data Science Specialization can prepare a student for an entry level data science job. If you're coming from a lower paid profession (e.g. a middle-schoool or high school teacher in the United States), the curriculum can help you immediately get a better paying job, especially if you invest the effort in developing a github repository with high quality projects. On the other hand, if you're already in a higher paid profession (e.g. software developer), you may have to take a pay cut to gain the experience necessary to qualify for a data science job that pays more than your current job.

That said, beyond just completing the specialization, one needs to be able to discuss the projects completed, the techniques used, and most importantly, how one developed the "hacker mentality" necessary to figure things out on one's own. I see this as the most valuable aspect of the specialization for a beginning data scientist, because it changes the interview from "what do you already know?" to "how I can learn enough to solve any ambiguous problem quickly."


Capstone as the Ultimate Embodiment of the Hacker Mentality

The Capstone project embodies all the things that are both exciting and frustrating about Data Science. Students must build a prediction algorithm in an area that is new to most students: natural language processing. The data source is a corpus of over 4 million English language texts from blogs, news sources, and twitter.

The assignment is deceptively simple: build an algorithm to predict the next word in a sentence, using the data provided for the project. Incorporate the algorithim into a Shiny application that can be installed on for peer review. The amount of instruction is minimal: weekly lectures consist of 1 - 3 minutes worth of content, plus references to academic papers in the area of natural language processing.

Students must do a considerable amount of work to solve the following challenges while building the predictive text application.

  1. How much memory is consumed by the data relative to the compute power I have?
  2. How do I select one or more R packages that produce the deliverables I need to build my algorithm, and run efficiently on my computer?
  3. What does "good" look like for a text prediction algorithm?
  4. How much data can I use in my prediction algorithm, given the processing limits of the free account? The three key considerations are load time, total memory used, and response time for predictions.

Finally, students must contend with a number of conflicting constraints and diverse commentary from other students, ranging from the desire to implement sophisticated algorithms like the Katz Back Off Model versus the resources needed to execute it, to students who encourage others to implement the models on the Amazon EC2 cloud.

It takes a lot of self-discipline to wade through the natural language processing theory, figure out what one can actually execute given the compute power one has, and avoid time sinks (e.g. figuring out how to do the project on Amazon EC2 without prior experience) in order to produce a working prediction app that runs on That said, the guidance I provide to students enrolled in R Programming: Strategy for the Programming Assignments still rings true: make it work, make it right, make it fast.

It's encouraging to know that the instruction provided in R Programming provides a good foundation for tackling the challenges of the capstone course. If you've been developing your hacker skills since R Programming, you're ready to take on the challenges of natural language processing.

Completing the Capstone is not easy. In fact, of the over 4 million people who have taken at least one JHU data science specialization course on Coursera since 2014, only 6,235 people had completed the capstone as of August 2017. For those who persevere and complete the capstone project, there is a well deserved sense of accomplishment at solving a very challenging natural language processing problem. Having finished the Specialization, students are well equipped to tackle real life data science problems.

JHU Data Science Team Ask Me Anything Session

To provide additional background on how the professors think about the curriculum, here is a link to the Ask Me Anything session that the JHU Data Science team conducted on Reddit in early 2016.

Hat tip to a Community Mentor, Stephanie Clark, from the Exploratory Data Analysis course.


Thanks to David Hood and Alan Berger for feedback about the value of quizzes as a sandbox that I've incorporated into the article.

About the Author

More information about the author is available on Len's LinkedIn profile page.