Skip to main content

How To Work a Sigmoid - Part Two

Software Development in Really Big Steps
  1. How To Work a Sigmoid
  2. How To Work a Sigmoid - Part Two

The last time I wrote about the curvature of project estimations, I was just speculating. Since then, I've discovered that FogBugz does track estimation over time, with a daily estimation record, and offers a graph of the 0, 50, and 100 percent estimates over time. I've been watching this develop for a small time, working more with tracked estimates, and I think some expansion on my thoughts is ready.

You can see my own estimation graph here and it demonstrates exactly what I predicted. I suspect a more complex plotting of points would emerge with the length of the project, but I have a few curiosities about how this would expand over time. The basic prediction of a generally unchanging estimation from the start, an increase in the estimation's growth in the middle, and ending with a calming and final flattening on the systems best guesses, as you slow down how many cases you file for every case that you close.

Steep hills in the estimation happen because for every case you close, you file some bugs, related features, and other cases that were brought to light or just gotten around to filing at that time. You can break down the states of case closure versus creation into three.

When you complete work in line with estimates, then things are On Track. This is misleading, but a good state at any rate. If you have ten hours worth of cases, spend 4 hours, and close about 4 hours worth of estimated cases, the target times on the project remain steady. If you keep this up until all the cases are closed and the project is finished, you can consider your estimations successful. Of course, it is more complicated.

As the design and plans are fleshed out, you'll find developers file more bugs than they close. The estimation is pushed further and further back. This isn't because the project gets more complicated or behind, although it could be so, but that the bulk of the estimation cases needed to represent the entire work of the project hasn't been filed yet. If we could design the entire thing up front, enter the cases, and never change them, we could keep a static estimation, if we remained On Track. We know that we can not and should not design everything up front, so we need to understand and work with changing estimations.

I'm going to make a second prediction about the estimation curve. I predict the curve presents itself in many steps. There are likely to be spurts of case filing and periods of working steadily on those that exist. The developers may have these steps in overlap. Taking some steps back, the steps will smooth into a larger, similar curve for the entire project. Each of these filing spurts will be the start, work, and wrapping up of some component inside the greater breadth of the project.



Comments

Popular posts from this blog

Interrupting Coders Isn’t So Bad

Here’s a hot take: disrupting coders isn’t all that bad.

Some disruptions are certainly bad but they usually aren’t. The coder community has overblown the impact. A disruption can be a good thing. How harmful disruption might be a symptom of other problems.

There are different kinds of disruptions. They are caused by other coders on your team, managers and other non-coders, or meetings throughout the day.

The easiest example to debunk is a question from a fellow developer. Imagine someone walks over to your desk or they ping you on Slack, because they have “one quick question.” Do you get annoyed at the interruption when you were in the middle of something important? You help out your teammate quickly and get back to work, trying to pick up where you left off. That’s a kind of interruption we complain about frequently, but I’m not convinced this is all that bad.

You are being disrupted but your team, of which you are only one member of the whole unit, is working smoothly. You unstuck …

CARDIAC: The Cardboard Computer

I am just so excited about this.


CARDIAC. The Cardboard Computer. How cool is that? This piece of history is amazing and better than that: it is extremely accessible. This fantastic design was built in 1969 by David Hagelbarger at Bell Labs to explain what computers were to those who would otherwise have no exposure to them. Miraculously, the CARDIAC (CARDboard Interactive Aid to Computation) was able to actually function as a slow and rudimentary computer. 
One of the most fascinating aspects of this gem is that at the time of its publication the scope it was able to demonstrate was actually useful in explaining what a computer was. Could you imagine trying to explain computers today with anything close to the CARDIAC?

It had 100 memory locations and only ten instructions. The memory held signed 3-digit numbers (-999 through 999) and instructions could be encoded such that the first digit was the instruction and the second two digits were the address of memory to operate on. The only re…

How To Care If BSD, MIT, or GPL Licenses Are Used

The two recent posts about some individuals' choice of GPL versus others' preference for BSD and MIT style licensing has caused a lot of debate and response. I've seen everything as an interesting combination of very important topics being taken far too seriously and far too personally. All involved need to take a few steps back.

For the uninitiated and as a clarifier for the initiated, we're dealing with (basically) three categories of licensing when someone releases software (and/or its code):
Closed Source. Easiest to explain, because you just get nothing.GPL. If you get the software, you get the source code, you get to change it, and anything you combine it with must be under the same terms.MIT and BSD. If you get the software, you might get the source code, you get to change it, and you have no obligations about anything else you combine it with.The situation gets stickier when we look at those combinations and the transitions between them.

Use GPL code with Closed S…