Should I Use R?               (See comparison of Excel & R Trellis Charts: video)

In pursuing my interests in data visualization, I have found several authors who have really had an impact on my graphical analysis thinking:

Edward Tufte - I first started my data visualization journey when I by read Tufte's Visual Display of Quantitative Information. While comfortable with Tufte's concepts, I found I needed more concrete examples and tools. This lead me to Naomi Robbins's book.

Naomi  Robbins' Creating More Effective Graphs book opened my eyes to a wide array of practical charting techniques not available in Excel. I was particularly interested in dot plots and trellis plots. Robbins' book is where I first learned about the R, S, and S Plus statistical and graphics languages.  Her chart examples and discussion lead me to William Cleveland's and Paul Murrell's books.

William Cleveland' s Elements of Graphing Data and  Visualizing Data books showed me that I was just scratching the surface of graphical analysis with default Excel charts. In addition to trellis displays, Cleveland's books showed me important concepts like banking to 45^o and locally weighted  regression (Lowess). 

Paul Murrrell's R Graphics  showed me the power of the R graphics package.

As I read Robbins, Cleveland and Murrell's books, I saw a number of data analysis and charting capabilities that I wanted to add to my repertoire:

• Trellis charts ( I started with horizontal and vertical panel charts in Excel)

• Box plots

• Dot plots

• Banking to 45^o - (Uses Excel Solver)

• Lowess ( No Excel progress)

While trying to make these advanced Excel based charts,  I often asked myself the question "...should I use R for this chart instead of  Excel". Based on Robbins' book, I knew that these charts were readily available in R.

Reluctant to take on the R learning curve, I developed several of the advanced charts in Excel and VBA. I knew it was taking more time than it would to use a high quality statistical analysis and graphing package. I felt that it was better to use a tool that I knew and avoid the learning curve of a package like R.

I made good progress building dot plots, box plots and banking to 45^o tools in Excel. Trellis charts  and Lowess smoothing proved a real challenge in Excel. Trellis charts allow the user to show multivariate data much more effectively than Excel's default charts. I looked into R again  and considered using R for my trellis charting needs. Rather than switch to R at that time, I started developing horizontal and vertical panel charts in Excel, wanting to be able to automate the development of a full trellis chart.

I searched high and low for a reasonable Lowess algorithm that I could incorporate into Excel. No luck.

I finally developed a set of VBA procedures to build a full trellis chart.  When I completed the Excel - VBA trellis chart, I reconsidered R because I now know what it will take for me to develop the trellis advanced charting that was already available in R.

Why reinvent trellis charts in Excel when they were readily available in R?  To answer this question, I needed to find out how difficult the R learning curve was, I already knew what it takes to develop these tools in Excel - VBA.

Trellis Chart in Excel and R

This video shows my Excel VBA trellis chart tool as well as the results of my 2 day R learning curve.

Based on my Excel - VBA trellis chart development time versus R trellis chart learning curve time, I will be using R for graphics that is not part of Excel's standard tools kit. I'd rather use a proven tool by a R programmer than reinvent my own graphic wheel in Excel.

I have a long way to go in mastering data analysis and time series analysis. I'd rather spend my time learning and using analysis  techniques rather than coaxing Excel to do what R can already do.

R Resources