Spider Maths

A sponsor asks why a one-line configuration change to a live system takes three weeks. The engineer who would make it says, quite honestly, that the change itself takes about a minute. Both are telling the truth, and the space between those two answers is where a PMO earns or loses its credibility.

Spider Maths is a small, memorable idea for explaining that space, then doing something about it. We picked it up from a clinical psychologist’s video about self-compassion and adapted it to delivery. It is honestly more of a thought experiment than a method, and that is fine: most useful models started that way. This one earns its place by being memorable, because the models people remember are the ones that get used.

Where Spider Maths comes from

Spider Math was coined by Dr Daniel Wendler, a clinical psychologist and a proudly autistic self-advocate, in a short video on his TikTok channel (@autisticpsychologist). Writing for a US audience he calls it Spider Math; we have kept the British spelling, Spider Maths, for the delivery version here. His point is about self-compassion, not project delivery. Setting the table is easy, he says. Setting a table covered in spiders is hard, and nobody would call the person who avoided that table lazy. When you work out how difficult a task is, you have to add in the spiders: the invisible load that makes an apparently simple job genuinely hard. Writing from his own experience, Wendler’s spiders are things like sensory sensitivity or burnout. Getting the groceries is easy; getting the groceries with a sensory sensitivity to the shop is much harder.

The self-compassion is something that arguably should be applied to project teams working within frameworks where they have no control over the ‘spiders’ that make project tasks hard, or overwhelming.

The model defined here is a thought exercise in (1) understanding and encouraging self-compassion, while (2) encouraging PMOs as agents for change and as framework owners to look for spiders and actively remove them to make delivery easier.

“Setting the table equals easy. Setting the table plus spiders equals hard. That’s spider math.”

Dr Daniel Wendler, in the original video.

The spider arithmetic

The model is one line of mental arithmetic. Perceived difficulty equals intrinsic difficulty plus spiders.

Intrinsic difficulty is the task itself: the minute at the keyboard. Spiders are everything else standing between wanting the task done and the task being done. Calling a job easy, or calling a person slow, is usually a sum with the spiders left out.

The model has two moves. The first is naming the spiders: a vague sense that everything here takes forever becomes a specific list, such as two approval boards, a hand-off to a separate infrastructure team, and a test environment booked a week ahead. Once named, a spider stops being a character flaw and becomes a problem you can work on. The second move is spider subtraction: you remove specific spiders rather than trying harder at the whole task. Wendler’s version is getting help and support. Ours is redesigning the path the work has to travel.

How a PMO uses Spider Maths

The "it only takes a minute" conversation

The first use is communicative. When a client looks at what they see as a small change to an app and cannot understand why it will take weeks, the honest answer is spiders. The change might be sitting behind other priorities on the backlog. It might need several hand-offs between different teams or projects. There might be a slow deployment pipeline it has to pass through, or an approval process so cumbersome that getting the sign-off takes more effort than making the change. Spider Maths gives a practitioner a calm, even light-hearted, way to have that conversation. It works in both directions too: it stops delivery teams and business stakeholders quietly labelling each other as lazy or obstructive.

Task effort is not the same as elapsed time

Effort is minutes. Elapsed time is minutes plus spiders. Confusing the two is at the root of most arguments about estimates. Lean thinking has named this distinction for decades: Rother and Shook’s Learning to See separates the processing time a task actually needs from the lead time it takes to travel through every queue and hand-off. Spider Maths is a friendlier way to teach the same point. If you want the mechanics behind why elapsed time outgrows effort, The Critical Chain Method covers task durations and buffers in detail.

Spider subtraction is PMO work

A PMO is one of the few functions placed to remove spiders rather than only sympathise with them. Nobody wants a table full of spiders, so the PMO acts as spider-catcher and gets speed to market up by taking out the tasks that add no value. Real subtractions include fewer hand-offs between teams, delegated approval thresholds so small changes skip the board, standing test environments instead of booked ones, and work-in-progress limits to thin out competing priorities. A spider audit feeds naturally into an A3, and if your spiders live in the hand-offs between teams, Flight Levels Kanban is a good way to see them.

Some spiders are load-bearing

The discipline that keeps this honest: some spiders are controls that exist for a reason. Segregation of duties, a safety case, a regulatory sign-off. Pull one of those out and the table is clear, but the house falls down. A PMO’s job is to tell a subtractable spider from a load-bearing one, and to make the load-bearing ones cheap to live with rather than pretend they can go. We run our own ISO 9001 and ISO 27001 controls, so we know the difference between a control that earns its keep and one that is just a spider in the way. Cass Sunstein’s Sludge makes the same case in behavioural terms: it names the administrative friction that stops people getting things done and proposes sludge audits to find and remove it. Spider subtraction is a sludge audit with a friendlier name.

Try it on your own delivery

We have built a one-page Spider Audit worksheet to turn this into an activity. List each task, its true effort and its actual elapsed time, then name every spider, mark it subtractable or load-bearing, and give it an owner.

Where Spider Maths stops

Spider Maths is a metaphor. It gives you a good conversation frame and a prompt to look for friction. It will not size that friction or tell you which spider to remove first. For that you need estimation and a proper look at your value stream.

It is also no substitute for taking action. If “spiders” become something to blame for every slippage, you have swapped one bad habit for another. The value is in naming specific spiders and removing them.

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How HotPMO can help

Spider subtraction is governance redesign: fewer hand-offs, delegated approvals, standing environments. That is the work we do. We help PMOs find the spiders in a delivery organisation, tell the subtractable ones from the load-bearing ones, and make delivery faster without tearing out the controls that matter.