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Improving data quality in data analytics & machine learning (Udemy.com)

Learn why, when, and how to maximize the quality of your data to optimize data-based decisions

Created by: Mike X Cohen

Last updated August 2026

Our take

Based on the ratings of 1,166 students, a sample of their written reviews and the syllabus, as the course stood in August 2026. No course pays to be reviewed.

This is a short, mostly conceptual course on data quality, taught by Mike X Cohen, a former neuroscience professor. It spends its first hour and a half on why quality matters and how to plan for it, then moves into assessing data and cleaning it. The Python code is optional and appears in the lectures that use pandas, numpy, seaborn and matplotlib. It suits analysts, students and the managers who work with them.

One reviewer calls the explanations easy to follow and describes the course as a nice browse through data quality and data preparation topics. Another praises the clear explanation of statistical themes. Of 1,166 ratings, 644 are five stars and 405 are four, so about nine in ten are positive. The complaints are small. Ninety-seven people gave three stars, and the one lukewarm review in our sample wanted Portuguese audio. The syllabus lists four quizzes and no coding exercises, so the code is something to watch more than practice.

At 5.4 hours across 45 lectures, it is quick to finish, and the last update was in August 2026, so it is current. The longest sections, on assessing data and on transformations, run about 90 minutes each. The syllabus and that 'browse' review point to a tour more than a workshop: it points to methods and shows them, but it will not turn a beginner into a cleaning expert. Worth it as a first pass at the topic, less so for anyone who wants heavy hands-on wrangling.

Best forAnalysts, students and managers who want a quick, conceptual grounding in data quality, with optional Python demos.
Skip it ifYou want hours of coding exercises on data cleaning, or audio in a language other than English.

Pros

  • Reviewers find Cohen's explanations easy to follow, including the statistical ideas
  • Covers planning, assessing, transforming and outlier handling in 45 short lectures
  • Python code for pandas, numpy, seaborn and matplotlib is optional, so managers can skip it
  • Updated in August 2026 and rated 4.6 from 1,166 reviews

Cons

  • No coding exercises and only four quizzes, so the Python is watch-along, not practice
  • One reviewer calls it a browse through topics, so depth on any one method is likely limited
  • Audio is English only, and one reviewer wished for a Portuguese version
Very insightful content, with clear explanation in statistical themes.
Oscar Alberto Sanchez Tobar, a student

Beginner level fits, though some Python helps if you want to follow the optional coding videos.

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What you will learn

  • Strategies for increasing data quality
  • Ways to assess data quality
  • Interpreting data visualizations
  • How to spot problems in data

Course content

9 sections · 45 lectures · 5.4 hours of video 4 quizzes, 1 article

  1. 1Introduction 1 free preview1 lecture · 7 min
  2. 2Download course materials (Python code)1 lecture · 3 min
  3. 3Why data quality matters 1 free preview5 lectures · 1 quiz · 18 min
  4. 4Ensuring high data quality 1 free preview10 lectures · 2 quizzes · 55 min
  5. 5Assessing data quality 1 free preview9 lectures · 1 quiz · 1.5 hours
  6. 6Data transformations 1 free preview8 lectures · 1.5 hours
  7. 7Outliers and missing data 1 free preview6 lectures · 49 min
  8. 8Be a high-quality data scientist4 lectures · 15 min
  9. 9Bonus1 lecture

Who it is for

The instructor says it suits

  • Data science practitioners
  • Data scientist students
  • Managers or colleagues who work with data practitioners

What you need before you start

  • Interest in working with data
  • Interest in knowing more about data quality
  • Some Python skills are useful for the optional coding videos

How it compares

Against the other 461 rated Udemy courses in Data Science on CourseDuck:

  • Rating4.6 out of 5higher than 67% of them
  • Reviews1,166#132 of 462 by number of reviews
  • Length5.4 hoursshorter than 65% of them
  • Last updatedAugust 2026more recently than 85% of them

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Course Description

All of our decisions are based on data. Our sense organs gather data, our memories are data, and our gut-instincts are data. If you want to make good decisions, you need to have high-quality data.


This course is about data quality: What it means, why it's important, and how you can increase the quality of your data.


In this course, you will learn:

  1. High-level strategies for ensuring high data quality, including terminology, data documentation and management, and the different research phases in which you can check and increase data quality.

  2. Qualitative and quantitative methods for evaluating data quality, including visual inspection, error rates, and outliers. Python code is provided to see how to implement these visualizations and scoring methods using pandas, numpy, seaborn, and matplotlib.

  3. Specific data methods and algorithms for cleaning data and rejecting bad or unusual data. As above, Python code is provided to see how to implement these procedures using pandas, numpy, seaborn, and matplotlib.


This course is for

  1. Data practitioners who want to understand both the high-level strategies and the low-level procedures for evaluating and improving data quality.

  2. Managers, clients, and collaborators who want to understand the importance of data quality, even if they are not working directly with data.

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Instructor Details

Mike X Cohen

I am a full-time educator and writer, and former professor of neuroscience. I "retired" from that position so I could focus my time and energy creating high-quality educational material just for you.

I have 20 years of experience teaching programming, data analysis, signal processing, statistics, linear algebra, and experiment design. I've taught undergraduate students, PhD candidates, postdoctoral researchers, and full professors. I have taught in "traditional" university courses, special week-long intensive courses, and Nobel prize-winning research labs. I have >100 hours of online lectures on neuroscience data analysis that you can find on my website and youtube channel. And I've written several technical books about these topics with a few more on the way.

I'm not trying to show off -- I'm trying to convince you that you've come to the right place to maximize your learning from an instructor who has spent two decades refining and perfecting his teaching style.

Over 350,000 students have watched over 50,000,000 minutes of my courses. Come find out why!

I have several free courses that you can enroll in. Try them out! You got nothing to lose ;)

                                                  -------------------------

By popular request, here are suggested course progressions for various educational goals:

MATLAB programming: Get Started with MATLAB; Master MATLAB; Image Processing

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Reviews

4.6

1,166 ratings on Udemy

Select a bar to show only those reviews.Select the bar again to show every rating.

By Zeba Warsi on 8/13/2026

Yes it is a good match for me

By Varian Mores on 6/29/2026

so nice, kinda difficult but challenging.

By Kannan P on 6/16/2026

Good and effective

By R Bhuvaneshwari on 4/17/2026

This course helped me understand the concepts clearly.

By Arit Glicksohn on 3/31/2026

Very thoughtful and engaging lectures

By Deepak Khande on 3/7/2026

Good content and very simply explained.

By Swapnil Bhavsar on 2/24/2026

mind-blowing course content

By Michaela Trimmel on 1/7/2026

I am now within Section 6 (that is the third hour of the course). It is easy for me to follow along his explanations. The course is a nice browse through different topics of data quality and data preparation.

By Oscar Alberto Sanchez Tobar on 10/31/2025

Very insightful content, with clear explanation in statistical themes.

By Leandro Donizete de Souza on 10/14/2025

O audio poderia ser em portugues mesmo que feito via IA ou Speech

Showing all 10 reviews on CourseDuck

Read all 1,166 reviews on Udemy

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Quality Score

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Overall Score : 92 / 100