One of the hardest biases I’ve had to overcome in my quant journey is what I call the reinvention bias.
It goes something like this:
“If I don’t build everything from scratch, then my work isn’t original or valuable.”
I had this bias for years. And I see it over and over again in calls, whether it’s with private investors, quants, or discretionary researchers dipping their toes into systematic strategies.
The instinct makes sense. We’re wired to think originality = edge. But in practice? Reinvention bias is one of the most dangerous traps in quant research.
The Reality
Platforms like Portfolio123 already embed over 20 years of quant R&D:
Proven ranking systems
Dynamic Universes
Curated factor / feature libraries
OOS Live Strategies
Research Groups with a ton of models
Free Designer Models
Rebuilding all of that from scratch isn’t just unnecessary - it’s counterproductive. Every hour spent re-coding Value, Growth, or a Momentum rank from scratch (!) is an hour you aren’t spending on the higher layers where your edge truly compounds.
Worse, it delays progress. By the time you’ve “proven” that a static (!) factor like Value (“forward value” still works well) on its own doesn’t work (something veteran quants have known for years), you’ve lost months you could have invested in more creative directions.
The Four Big Tickets in Systematic Investing that you do not have to reinvent!
What makes P123 unique is that it has all the essential components under one roof. These are the four big tickets:
Great PIT Data
Point-in-time, survivorship-bias-free data across more than 1,000 factors and features: technicals, fundamentals, analyst estimates, actuals, and sentiment.
This is the raw material for any serious quant system.Ranking Systems
The ability to combine, weight, and structure factors into interpretable ranking models that drive stock selection.Strategy Books
Portfolio-level construction, combining multiple strategies into one strategy book.
This allows for diversification, liquidity scaling, cross-factor mean reversion, and alignment with institutional mandates.AI Factor
Modern machine learning layered directly into the ranking framework, built on conservative, point-in-time data. This bridges the gap between classic quant factors and adaptive AI signal extraction.
These four pillars mean you don’t need to reinvent infrastructure. P123 already solved the baseline. Our job is to put creativity into the higher-level design choices!
The Better Path
The edge isn’t in reinventing factors. The edge is in what you build on top of them.
Start with Proven Foundations
Use out-of-the-box P123 ranking systems, universes, and factor / feature libraries. These are the engines—battle-tested and robust.Direct Creativity Where It Compounds
Feature curation and combinations — adding features and nuance to existing ranking systems and making them your own.
AI layering — integrating AI Factor models into ranks to capture non‑linear signals.
Buy rules and overlays — applied sparingly; I use only 3–5 light rules that avoid heavy assumptions, serving as filters rather than rigid frameworks.
Risk design and position sizing — structuring exposure, turnover, and drawdown
Combining portfolio strategies — blending systems with relatively low covariance in Strategy Books (this is super important) to achieve diversification and cross‑factor mean reversion. Add volatility suppressors like gold or defensive sleeves for stability investors can trust.
My Personal Lesson
AT LEAST 80% of my current work builds directly on top of the models Portfolio123 provides.
That IS MY foundation.
The other 20% — my curation of features, my design choices, my overlays, my AI integration — is where the magic happens.
The Takeaway
Edge isn’t in reinventing. Edge is in leveraging what’s proven — and then building on top.
Reinvention feels smart but is mostly ego.
Many quants (especially retail or early-stage) burn years trying to “beat” the baseline models by rebuilding Value, Momentum, Growth, etc. from scratch. It scratches the intellectual itch, but is not very productiveLeverage feels unoriginal but is where real compounding happens.
If you start with a robust infrastructure (P123’s PIT data, ranking systems, strategy books, AI Factor), you already have what most quants spend a decade assembling. That frees you to spend time on the differentiators — overlays, feature selection, portfolio construction, cross-factor mean reversion, volatility suppressors.The true edge is creative leverage.
Creativity applied on top of proven infrastructure compounds in ways that starting from scratch simply doesn’t. That’s where people carve out real advantages.
If you’re serious about systematic investing, do yourself a favor: overcome the reinvention bias sooner than I did. It will save you years of wasted time and unlock the compounding power of your creativity.
Best Regards
Andreas