What 108M Lines of Code Tell Us
Results of the first annual report on application quality have just been released by CAST. The company analyzed 108M lines of code in 288 applications from 75 companies in various industries. In addition to the ‘usual suspects’ – COBOL, C/C++, Java, .NET – CAST included Oracle 4GL and ABAP in the report.
The CAST report is quite important in shedding light on the code itself. As explained in various posts in this blog, this transition from the process to its output is of paramount importance. Proficiency in the software process is a bit allusive. The ‘proof of the pudding’ is in the output of the software process. The ability to measure code quality enables effective governance of the software process. Moreover, Statistical Process Control methods can be applied to samples of technical debt readings. Such application is most helpful in striking a good balance in ‘stopping the line’ – neither too frequently nor too rarely.
According to CAST’s report, the average technical debt per line of code across all application is $2.82. This figure, depressing that it might be, is reasonably consistent with quick eyeballing of Nemo. The figure is somewhat lower than the average technical debt figure reported recently by Cutter for a sample of the Cassandra code. (The difference is probably attributable to the differences in sample sizes between the two studies). What the data means is that the average business application in the CAST study is saddled with over $1M in technical debt!
An intriguing finding in the CAST report is the impact of size on the quality of COBOL applications. This finding is demonstrated in Figure 1. It has been quite a while since I last saw such a dramatic demonstration of the correlation between size and quality (again, for COBOL applications in the CAST study).
Source: First Annual CAST Worldwide Application Software Quality Study – 2010
One other intriguing findings in the CAST study is that “application in government sector show poor changeability.” CAST hypothesizes that the poor changeability might be due to higher level of outsourcing in the government sector compared to the private sector. As pointed out by Amy Thorne in a recent comment posted in The Agile Executive, it might also be attributable to the incentive system:
… since external developers often don’t maintain the code they write, they don’t have incentives to write code that is low in technical debt…
Congratulations to Vincent Delaroche, Dr. Bill Curtis, Lev Lesokhin and the rest of the CAST team. We as an industry need more studies like this!