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L.6 · INTERMEDIATE · 2 MIN

Model-Output Discipline: Models That Explore vs Models That Defend

A model can produce the same number two ways. In the first, the analyst sets assumptions from independent evidence and reads the answer. In the second, the analyst starts from a desired answer and tunes assumptions until the model agrees. The first is exploration; the second is defense. The output looks the same. The reliability is not.

Quiz · 5 questions ↓
§ 01

The structural test for whether a model is exploring or defending is workflow ordering. An exploring model builds inputs from named, dated, sourced evidence BEFORE the analyst writes down a target price. A defending model starts from the target — often anchored to the current price plus a familiar 15-20% upside — and reverse-engineers the assumptions. Both produce a number; only one of them is useful for decisions.

§ 02
BehaviorExploring modelDefending model
Assumption sourcesEach input has a named source (filing line, peer mean, industry report)Inputs are "around peer level" or "in line with management"
Sensitivity tableShows where the answer breaks; analyst notices and reports the breakSet up after the fact to show the answer is "robust"
When evidence contradicts an inputInput gets updated; output moves; analyst writes down the moveInput gets reframed ("that data point is noisy") to preserve the output
Round-trip with current priceCompared after the model is built, not beforeDrives the build from the start
What the analyst reports if model says SELLReports SELL or explains why the model is wrong about the situationTunes inputs until model says HOLD or BUY
§ 03

Worked example — two analysts model Brixmor Networks. Analyst A pulls last-three-year revenue growth (8.2% mean), peer terminal-growth medians (2.5%), and a CAPM cost-of-equity build with named beta and risk-free rate. She runs the model and gets $43. Current price is $54, so she reports SELL with a $43 base case and writes a one-page note on why peers may be over-paying for the segment. Analyst B sees the stock at $54, opens the same model, and types in terminal growth of 3.5% ("justifiable" he says), revenue growth of 11% ("sell-side is too low"), and discount rate of 7.5% ("low-beta name"). He gets $61 and reports BUY with a $61 target. The outputs differ by 40%. The model is identical. The process is not.

§ 04

Practical defense for the analyst-on-themselves: write the assumptions in a separate document BEFORE opening the spreadsheet. Stamp each assumption with the source. Build the model. Then look at current price. If the answer needs to move materially to "justify" the output, do not nudge — investigate what evidence would have to be different for the answer to move that far, and check whether that evidence exists. Most of the time it does not, and the right answer is to accept the model's number or kill the idea.

§ 05
An analyst's model produces a $32 target on Pelham Holdings, which trades at $52. The analyst's first instinct should be:
§ 06

Track which models you have nudged after seeing current price. If you cannot remember a single case where your model produced an answer you did not like and you reported it anyway, you are defending, not exploring. Useful analysts produce uncomfortable answers regularly.

Five questions · AI feedback

Sit with the ideas.

An analyst's DCF on Brixmor Networks produces a $58 intrinsic value. The stock trades at $54. The analyst's terminal-growth assumption is 3.0% and the discount rate is 8.5%. Which of the following BEST diagnoses whether this is an exploring model or a defending model?

Why:
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