Complexity Screening: 5 Questions to Ask Every New Tax Client

Not every Self Assessment return needs the same level of review. The mistake most firms make is deciding complexity by gut feel, after preparation has already started — which is exactly when a junior preparer discovers they're out of their depth halfway through a return.

Screen for complexity at intake instead, with five yes/no questions.

The five questions

Property disposals — did they sell a property other than their main home this tax year?

Multiple income sources — income from more than two distinct sources (employment, self-employment, property, dividends, foreign)?

Foreign income or assets — any income, gains, or accounts outside the UK?

Capital gains beyond shares — disposals of business assets, crypto, or other chargeable assets?

First year as this client type — newly self-employed, newly a landlord, newly a director this year?

Turning answers into a tier

Zero flags: Simple. A junior preparer can handle it with a light, spot-check review.

One flag: Standard. Junior preparer, but with senior sign-off, and a full review of the flagged section specifically rather than the whole return.

Two or more flags: Complex. Assign to a senior preparer from the start, with a full line-by-line review before client sign-off.

Why this matters more than it looks like it should

Complexity mis-assignment is expensive in a specific way: it either wastes a senior preparer's time on a return that didn't need it, or it puts a junior preparer into territory where mistakes are more likely and take longer to catch. Both cost more time than the two minutes it takes to run five questions at intake.

The part screening doesn't catch

Screening happens once, at intake, based on what the client tells you up front. It won't catch a complexity flag the client didn't mention — a property sale they forgot to flag, a foreign account they didn't think was relevant. When that surfaces mid-preparation, reassign to a senior preparer immediately rather than letting a junior push through unfamiliar territory to save time.

Complexity tier is one of five branch points that determine how a tax season client moves through your firm. The Tax Season Operations Playbook covers the full system, including what to do when complexity is discovered late.