May 03, 2020
This course provides an introduction of some important concepts and tools on a very important aspect of data science: cleaning and organizing data before any analysis. A must for any data scientist.
Oct 26, 2016
This course is really a challenging and compulsory for any one who wants to be a data scientist or working in any sort of data. It teaches you how to make very palatable data-set fro ma messy data.
von Chuang M•
Feb 07, 2016
von Marcos A•
May 12, 2019
von Nithin K G•
Nov 16, 2018
von Ashish S•
Feb 06, 2017
von shipra g•
Aug 08, 2016
von Vivekananda R C•
Feb 08, 2016
von Dimitri d•
Feb 23, 2017
von Sergio R•
Nov 27, 2016
Oct 23, 2016
von Borja C•
May 07, 2016
von Raw N•
Apr 07, 2017
Would have preferred if there were programming assignments that incorporated reading from data sources on the web.
For those planning to take the course, note the following:
*The course covers reading data from a myriad of sources, but largely in passing superficial detail. These sources include XML files, mySQL databases, HDF5 files, csv files, txt files with various formats (for example fixed-with files), JSON objects, and web API.
However, the course project only involves reading data from several txt files and combining them into a single R dataset.
Course topic order: In the first two weeks of the course, a lot of information is glossed over in passing- this information involves reading from the various file formats mentioned above. Week 3 involves subsetting, sorting, reshaping and merging data. Some of this may be review for you if you've taken the R programming course or the "R Programming Environment" course in the "Mastering Software Development in R" specialization. Week 4 involves string manipulation, regular expressions and working with the Dates. A lot of this is covered in Roger Peng's ebooks "R Programming for Data Science" and "Mastering Software Development in R" (both are freely available- google them).
Assessments: The only assessments in the course are 4 quizzes- each of which involves about 5 short programming exercises- and a final project which only involves topics from weeks 3 and 4 (specifically- subsetting data, sorting data, reshaping data, and working with regular expressions). So you can do the course project without understanding anything covered in weeks 1 and 2 of the course.
Mentor David Hood is fantastic for providing valuable resources to aid you with each assessment and so is Xing Su for providing a complete set of course notes. USE THE DISCUSSION FORUMS IF YOU GET STUCK!
von Miguel C•
Mar 25, 2020
I really enjoyed and learned a lot in this course.
I feel a lot more comfortable with looking for and reading data. I learned how to clean data and getting it ready for further analysis. I think the course project was particularly good for completely understanding the process of tidying data and all the aspects it involves, such as writing a code book and a README file for accompanying it.
Furthermore, I believe I further developed my R programming skills, by learning how to code new things or things I already knew but in a more efficient way, by using new packages and techniques.
Moreover, I found Professor Jeffrey Leek quite engaging, very easy to understand and I had complete confidence in his knowledge on this subject.
However, I believe the course is slightly outdated. I was often disheartened and frustrated by not being able to replicate what was being done in the lecture videos. For example, there were many links that did not work anymore and sometimes information that simply wasn't correct anymore. I found the discussion forums and many mentors responses to be very helpful. I think this can easily be fixed by writing up an errata or updating the lecture videos.
von Tomasz J•
Dec 11, 2017
The course is teaches you some principles of tidy data and cleaning data but it's very messy.
There is no systematic approach to plyr and dplyr libraries. The teachers peak some functions from one and some functions from other library, but without any clear principle. It looks that prof. Leek and prof. Peng are presenting their favorite functions without consulting each other. They are doing it in the right way, though very confusing. On the other hand loading data is approached very encyclopedically.
Assignments not only check what was taught in the videos but also sometimes require new skills and going through stackoverflow etc. (e.g. codes to read fortran files). This is not the way how you construct good coursers.
Additionally some instruction in the final assignment are provided in submission part! (Expected names of the files should be provided in the assignment description, not on the submission page).
Prof. Peng and prof. Leek are very skilled, they know their job, but they don't know how to teach efficiently. Nonetheless if you are motivated to learn, this course may be very helpful.
von Guillermo A G•
Oct 23, 2017
This course was quite challenging in comparison with the first two. I felt that the material provided by the instructors was not enough to approach the quizes and assignments, so it's necessary to spent a lot of time researching for your own in other sources. I struggled with the Course Project Assignment because I didn't understand what I was supposed to do exactly. Fortunately, the forum threads were really helpful. Nevertheless, the course's intention is very valuable and if you are patient and go all the way through it you will improve your data science skills, learn very useful techniques and habits, specially if you're a beginner. But I strongly suggest the instructors to make the course contents more explicit and helpful.
von John Y•
Aug 05, 2017
Great class for an important piece of data analytics and data science. One issue I've been noticing with R compared to using Anaconda/Python is that a lot of the libraries required for the class aren't explicitly mentioned. That's fine if you're experienced with these environments and able to read error codes with familiarity. Minor annoyance to me when I run a script and realize I don't have a library installed.
I'd imagine though its extremely frustrating for beginners who may have written perfectly good code but haven't figured out that they simply need to install certain packages to answer quiz or homework questions. Perhaps having a full library or package list for Course 1 of this series will be helpful.
von Dan S•
Oct 10, 2020
There was a lot to like about this course but there were several aspects that kept the course from being stellar. This course attempts to convey a lot of important information without connecting the dots. The videos did not align well with the Swirl exercises and the videos did not attempt to address foundational principles of the course topics. Rather, many topics were covered on a superficial level without in-depth examples that demonstrate application of the topics. I think the course needs to updated as some of the quiz questions and material seem to be out of date. The final project description had aspects that were vague and hard to interpret given the data set we had to work with.
von Joshua S•
Jul 10, 2020
Lecture content is very drab and filled with "...and here's another thing you can do...". I think it would be a lot more effective with more problems and various solutions. There should be a project every week along with the quizzes.
I also found the peer review process for the course project to be sub-par. I personally put a LOT of work into the course project, and put together what was a really thoughtful and well-written README and CODEBOOK just to have my project downgraded because someone wasn't sure the run_analysis did what it was supposed to. It's not a big deal but I think if an instructor saw it they would've found it very thoughtful, thorough and accurate.
von Jaymes P•
Oct 23, 2020
This course was largely helpful and the instructor was clear in the lectures. However, much like many of the courses in this specialization, the quizzes and the final project were misaligned with what was taught in the lectures. For example, we sit through a whole week of lectures on the details of reading in many different data types, but never talk about fixed-width format once, it's never even mentioned. And that is what is on the quiz. The final project was challenging and fun to figure out once I was on the right track, but the directions were not sufficiently clear and I wasted a lot of time needlessly simply trying to figure out what the instructor wanted.
von Anton K•
Aug 08, 2019
This is a very brief course, many of the topics deserve a much more thorough explanations. This part of the data analysis (i.e. data cleaning and acquisition) is in fact a complex subject and subjects are not covered in this course. There were also technical issues. For instance, the audio quality of lectures by prof. Jeff Leek is very poor. And the other major problem that I had with this course is the ambiguity of the requirements, although it wasn't difficult to finish. But if you are planning on taking this course, be ready to spend considerable amount of time on understanding the structure of the final submission's materials.
von Harris W•
May 27, 2020
Like all courses in this specialization, there is an incredible lack of practice and application for a large amount of the skills taught in lecture. I would say that only about 60 percent, or maybe less, of the content in the lecture is assessed in the quizzes and assignments. Additionally, the peer review process is wildly flawed for the final project. I did not receive any constructive criticism from anyone, and I doubt they even truly looked at my code to make sure it worked. I don't blame them, they have little incentive. Rather I place blame on the system of grading and lack of feedback.
von Rashaad J•
Jul 24, 2017
I have 2 key concerns with this course. First, I don't feel like the material presented adequately prepares you for the quizzes. For at least 2 of the 4 quizzes, I had to spend a substantial amount of time locating and reviewing other resources to answer the questions. My second concern is that for the final course assignment, there is a lack of specificity with the instructions. Not being able to answer a question is vastly different from not understanding what the question is asking and I found myself spending more time doing the latter (which is wasteful) and less time with the former.
von Constantin S•
Feb 20, 2016
In some weeks only about an hour of input where several topics have already been covered in R Programming. That's very little value for money.
The final course project again feels like it's done in a rush and without another review: The submitted dataset should be automatically checked. It's simply impossible to derive from it whether the student did everything right, but it could be easily done programmatically. Some of the questions have wording and grammar issues that make it hard to understand. Also there is slightly contradicting instructions between the task and review description.
von Angela W•
Jul 14, 2017
I did learn a lot, but I thought the first half of the course (getting the data) was very challenging.
What does annoy me though is that links aren't clickable, sometimes they're wrong, there are typos on the slides etc. The response to these complaints in the forums is that these lectures were recorded a while ago and it takes time to change things and so on - but for $50 a month, I don't think it's too much to ask that the course materials be kept up to date!
So honestly, I feel like I'm being ripped off a bit here.
I did really enjoy the course project though.
von Luis P•
Jan 25, 2018
The most challenging so far of the 9 courses on the Data Scientist track. Would like to see some errors removed from slides. Some parts of the lectures seemed rushed. Would like to see some of the non-self-evident usage of some functions to be described a little better in more detail. I found myself having to look at multiple online areas to really understand some of the functions that were glossed over. Otherwise, this was a very helpful course that should be taught to all disciplines involving any amount or type of data.
von Raymond B•
Sep 27, 2020
The "Reading from..." lessons from week 1 and week2 were extremely frustrating, since we did not get much info on where we would see them most often or the benefit of using one over the others. Instead, we simply sat for hours listening to lectures moving from one type of document to the next before being handed the quiz. The dplyr and data manipulation lectures were great and I really anticipate using them frequently in the future. I think regular expressions deserved more lecture time/ practice.