An XBRL Library for Perl

March 28, 2012 2 comments

I’ve been working for some time on a Perl module to parse XBRL, a complex XML based format for reporting financial information.  The US SEC requires   publicly traded firms to provide their financial reports in XBRL.  The goal of the Perl module is to provide a clear and easy to use interface to extract data from an XBRL instance and use it for another purpose.  In the initial release, the module features a function to render the XBRL instance into a very basic HTML document.   Because the XBRL standard is large and complex, support for its features will be added over subsequent releases.

Source code and project management is hosted at Github.  The module is available via CPAN here.

An Open Source WebOS

December 10, 2011 Leave a comment

Today’s announcement from HP that WebOS will be set free as an Open Source project opens up room for some interesting changes in the mobile landscape.  Both CNET’s Stephen Shankland  and The VAR Guy think nothing much will come of this move.  As both a long time Open Source zealot and a mobile developer, I think there is more there there than they do.

Read more…

More Statistics on Sacramento Housing

October 28, 2011 Leave a comment

In a previous post, I showed a pretty simple regression analysis of housing prices and house size for my Zip code. The zip code was used as an easy way to include location in the output. Using PostGIS and geographic data from the City of Sacramento, this post will show a regression analysis ( using the R statistical programming project) using the city’s designated neighborhoods. The raw data real estate data comes from the Sacramento Bee. After describing the model, I’ll apply it the last few months of home sales (not used in developing the model), and see how well it does at predicting results.    Read more…

D’oh! Not Again

August 19, 2011 Leave a comment

Having worked for many years at HP, the recent announcement cancelling HP’s Webos program is rich with personal irony. Until yesterday’s announcement, I was working on a bar code scanning application for HP’s Pre 3 phone.

Thinking about life as an independent “app” developer, I’m reminded of Canadian Prime Minister Pierre Trudeau’s famous remark about the United States:

Living next to you is in some ways like sleeping with an elephant. No matter how friendly and even-tempered is the beast, if I can call it that, one is affected by every twitch and grunt.

I hope the new PC company gets off to a good start and they get to keep WebOS, but they will have to move forward without my efforts as an “app” developer.

Using Statistics to Explicate the Sacramento Housing Market

August 10, 2011 Leave a comment

The Sacramento Bee has a home sale database for looking up the prices of home sales.  I was a little disappointed that it only listed the sales and didn’t do any Zwillow style statistical analysis.  So I dumped the data into R and started playing around with it.  Home price versus size versus number of bedrooms is always one of the text book examples for multiple regression, so I thought it would be pretty easy.  It turns out that the replicating the Zwillow estimate with real world data, is harder than it looks.  So, I’m going to start with smallest model I can get decent results with, and add build it up over a series of posts.  Below is a regression for Price and Size in the 95834 zip code.  Read more…

Categories: Business Ruminations

A Real World Example of A/B Website Testing

March 13, 2011 Leave a comment

A/B testing has gained a lot of interest in recent years as a practical method for improving the results from websites.  My business partner and I produced a mobile application, RecallCheck that relied on a database we created from FDA and USDA websites.  During our project, the FDA introduced a new website for reporting food related issues called the:  Reportable Food Registry.  For our purposes (using a mobile phones to scan bar codes), the result we most cared about was the quality and quantity of UPC codes.  Below is a detailed statistical analysis of before and after the FDA made it’s changes with regard to the quantity of UPC codes included in published recall notices.   While our interest was the UPC codes, the same process can be applied to any change on a website. Read more…

RecallCheck Post-Mortem

Recently, I’ve been answering a lot of questions about about RecallCheck, which was an Android based mobile application to allow uses to scan UPC bar codes on packaged food and find out about any recent recalls involving that product.  Developing and marketing RecallCheck, I worked with my business partner Scott. With the project is now over, I’d like to cover some of the learnings and reasons I believe we were ultimately unsuccessful. Read more…

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