How to Estimate Time Starting with Capacity

Most organization face a common challenge in how to account for and estimate the amount of time it takes to accomplish an initiative. There are elaborate ways to go about this ranging from tracking time or estimating with story points, although I recommend a simpler approach.

There are three components to this puzzle:

1. Capacity: how much time a person has
2. Estimations: how much time a piece of work might take
3. Allocations: how people are assigned or aligned to pieces of work

Today, we're going to tackle how to figure out capacity as a function of figuring out your maximum and the scale to use for measuring it.

Pretend there is an empty pint glass in front of you and I'm starting to pour water into the glass.

When do you tell me to stop pouring water?

Most likely when it's a centimeter or so from the top.

There's a good reason for this, as you may want to pick up your glass and walk with it or just avoid spilling it when it's time for a sip of water.

The high watermark is your actual capacity, not the top of the glass (that is your absolute capacity).

Most organizations think about maximum capacity as of 40 to 45 working hours.

Applying the glass mostly full metaphor, your actual capacity is lower than a 40 to 45 hour week, although the real issue with this measure is the scale that we're using.

Let's dump out the pint glass and start putting in ice cubes (not chips, pebbles, or whatever other artisanal types... just the standard, boring cubes).

Are you able to put in 40 cubes? What about 20?

Most likely you're only able to put in a dozen or so.

Also, if you look at those ice cubes, are they all the same shape, size, and weight?

Probably not.

The scale to measure your capacity is in blocks, not hours.

Because most of us are operating with five day work weeks, instead of focusing on hours, decide on whether you will use two or three blocks per day.

This means your absolute capacity (the top of the glass) is 10 to 15 blocks, although your actual capacity (high watermark) is lower than that by 10-20%.

Tomorrow, we're going to discuss how estimations align with our block scale.

TLDR: Start thinking about your capacity as two or three blocks per day with at most 8 or 12 per week respectively.