SLOC-wars

["Kent Paul Dolan" <xanthian@well.com>]

"M�rio Amado Alves" <maa@liacc.up.pt> wrote:

> You're both right. I also did a study correlating program text metrics
> and actual development cost in programmers*month. SLOC had the best
> results, notably beating Halstead. It was a small project (10k SLOCs if
> I remember correctly), but it was unbiased i.e. the programmers didn't
> know about the metrics in advance.


Well, but SLOC is predicting by hindsight, and it has been fairly well
known since the 1960's that individual programmer's code output is
fairly constant when measured in keystrokes, so that about as many lines
per day of assembly as of APL can be delivered fully burdened.

Thus, one would expect that SLOC or something like it  fairly equivalent
to keystrokes would be the best hindsight predictor of
technologist-months of effort involved in completing a project or a
component.

But I thought (with no expertise here) that the goal of stuff like
Halstead's metric was that you could estimate it at specification time,
and do foresight forecasting with that estimate.  I'd shudder to think
what the accuracy of foresight guesses at SLOC from similar projects
might accomplish in setting milestone dates and such.

Thus, in comparing a tool useful primarily for hindsight forecasting to
the detriment of one also useful for foresight forecasting, aren't you
doing the apples versus oranges thing?

xanthian.


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