Martin Krzywinski / Genome Sciences Center / mkweb.bcgsc.ca Martin Krzywinski / Genome Sciences Center / mkweb.bcgsc.ca - contact me Martin Krzywinski / Genome Sciences Center / mkweb.bcgsc.ca on Twitter Martin Krzywinski / Genome Sciences Center / mkweb.bcgsc.ca - Lumondo Photography Martin Krzywinski / Genome Sciences Center / mkweb.bcgsc.ca - Pi Art Martin Krzywinski / Genome Sciences Center / mkweb.bcgsc.ca - Hilbertonians - Creatures on the Hilbert Curve
syncopation & accordionCafe de Flore (Doctor Rockit)like France, but no dog poopmore quotes

art: exciting


UCD Computational and Molecular Biology Symposium, Dublin, Ireland. 1-2 Dec 2016.

design + visualization

VIZBI 2013 Keynote

Visual Design Principles—Communicating Effectively

This talk happened on Thursday, Mar 21st 2013 at VIZBI 2013 at the Broad Institute in Boston.

How often people speak of art and science as though they were two entirely different things, with no interconnection. An artist is emotional, they think, and uses only his intuition; he sees all at once and has no need of reason. A scientist is cold, they think, and uses only his reason; he argues carefully step by step, and needs no imagination. That is all wrong. The true artist is quite rational as well as imaginative and knows what he is doing; if he does not, his art suffers. The true scientist is quite imaginative as well as rational, and sometimes leaps to solutions where reason can follow only slowly; if he does not, his science suffers. —Isaac Asimov (The Roving Mind)

For more visualization and design resources, see my VIZBI 2012 tutorials, Nature Methods Points of View column, and rant about colors.

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Do not allow encoding or other design choices to hijaack your message. Each element on the page must meaningfully contribute to your figure.

presentation video

The video will be posted at vizbi.org.

presentation slides

Slides are available as PDF and keynote (zipped).

Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
Martin Krzywinski - VIZBI 2013 Keynote - Visual Design Principles
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A poet is, after all, a sort of scientist, but engaged in a qualitative science in which nothing is measurable. He lives with data that cannot be numbered, and his experiments can be done only once. The information in a poem is, by definition, not reproducible. He becomes an equivalent of scientist, in the act of examining and sorting the things popping in [to his head], finding the marks of remote similarity, points of distant relationship, tiny irregularities that indicate that this one is really the same as that one over there only more important. Gauging the fit, he can meticulously place pieces of the universe together, in geometric configurations that are as beautiful and balanced as crystals. —Lewis Thomas (The Medusa and the Snail: More Notes of a Biology Watcher)

breakout session—making good figures

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Sketch notes by the inimitable Francis Rowland from our breakout group. The question was: what do you need to make good figures? (PDF)

small, medium and big data visualization

If you're asking how to visualize big data, first make sure you're doing a good job on small and medium data. Each scale requires good design.

Do not expect to use one way
to tell many stories

Also consider that there is a very large number of combinations of data sets, hypotheses and possible patterns. Because of this, you cannot expect to use one way to tell many stories. There is no Holy Grail of big data visualization. But there are many good questions to ask and practices to follow that make up a process which can help you get there.

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Medium data visualization. This is what happens when you show the data (a strategy that works for small data), instead of explaining it. Yup, we need to work on this too. (A) Qi X et al. J Biotech 144:43 (2012) (Saturation-Mutagenesis in Two Positions Distant from Active Site of a Klebsiella pneumoniae Glycerol Dehydratase Identifies Some Highly Active Mutants) (B) Alekseyev, M.A. et al. Genome Res 19:943 (2009) (Breakpoint graphs and ancestral genome reconstructions)
Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Big data visualization. Yes, data sets are growing but are visual and cognitive abilities are not. There are many data sets, each requiring its own approach. You cannot use one way to tell many stories. Lewis SN et al. PLoS ONE 6:e27175 (2011) (Prediction of Disease and Phenotype Associations from Genome-Wide Association Studies)

upcoming

VIEW ALL

news + thoughts

Model Selection and Overfitting

Tue 13-09-2016

With four parameters I can fit an elephant and with five I can make him wiggle his trunk. —John von Neumann.

By increasing the complexity of a model, it is easy to make it fit to data perfectly. Does this mean that the model is perfectly suitable? No.

When a model has a relatively large number of parameters, it is likely to be influenced by the noise in the data, which varies across observations, as much as any underlying trend, which remains the same. Such a model is overfitted—it matches training data well but does not generalize to new observations.

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Nature Methods Points of Significance column: Model Selection and Overfitting (read)

We discuss the use of training, validation and testing data sets and how they can be used, with methods such as cross-validation, to avoid overfitting.

Altman, N. & Krzywinski, M. (2016) Points of Significance: Model Selection and Overfitting. Nature Methods 13:703-704.

Background reading

Lever, J., Krzywinski, M. & Altman, N. (2016) Points of Significance: Classifier evaluation. Nature Methods 13:603-604.

Lever, J., Krzywinski, M. & Altman, N. (2016) Points of Significance: Logistic regression. Nature Methods 13:541-542.

...more about the Points of Significance column

Classifier Evaluation

Tue 13-09-2016

It is important to understand both what a classification metric expresses and what it hides.

We examine various metrics use to assess the performance of a classifier. We show that a single metric is insufficient to capture performance—for any metric, a variety of scenarios yield the same value.

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Nature Methods Points of Significance column: Classifier Evaluation (read)

We also discuss ROC and AUC curves and how their interpretation changes based on class balance.

Lever, J., Krzywinski, M. & Altman, N. (2016) Points of Significance: Classifier evaluation. Nature Methods 13:603-604.

Background reading

Lever, J., Krzywinski, M. & Altman, N. (2016) Points of Significance: Logistic regression. Nature Methods 13:541-542.

...more about the Points of Significance column

Happy 2016 `\pi` Approximation, roughly speaking

Sun 24-07-2016

Today is the day and it's hardly an approximation. In fact, `22/7` is 20% more accurate of a representation of `\pi` than `3.14`!

Time to celebrate, graphically. This year I do so with perfect packing of circles that embody the approximation.

By warping the circle by 8% along one axis, we can create a shape whose ratio of circumference to diameter, taken as twice the average radius, is 22/7.

If you prefer something more accurate, check out art from previous `\pi` days: 2013 `\pi` Day and 2014 `\pi` Day, 2015 `\pi` Day, and 2016 `\pi` Day.

Logistic Regression

Tue 13-09-2016

Regression can be used on categorical responses to estimate probabilities and to classify.

The next column in our series on regression deals with how to classify categorical data.

We show how linear regression can be used for classification and demonstrate that it can be unreliable in the presence of outliers. Using a logistic regression, which fits a linear model to the log odds ratio, improves robustness.

Martin Krzywinski @MKrzywinski mkweb.bcgsc.ca
Nature Methods Points of Significance column: Logistic regression? (read)

Logistic regression is solved numerically and in most cases, the maximum-likelihood estimates are unique and optimal. However, when the classes are perfectly separable, the numerical approach fails because there is an infinite number of solutions.

Lever, J., Krzywinski, M. & Altman, N. (2016) Points of Significance: Logistic regression. Nature Methods 13:541-542.

Background reading

Altman, N. & Krzywinski, M. (2016) Points of Significance: Regression diagnostics? Nature Methods 13:385-386.

Altman, N. & Krzywinski, M. (2015) Points of Significance: Multiple Linear Regression Nature Methods 12:1103-1104.

Altman, N. & Krzywinski, M. (2015) Points of significance: Simple Linear Regression Nature Methods 12:999-1000.

...more about the Points of Significance column