The investment industry thrives on complexity. But decades of independent research tell a simpler story: evidence-based investing, built on low-cost, globally diversified funds, will outperform most professionally managed alternatives over time. Here’s why the smartest investment decision you can make may also be the most straightforward.
Most of us, at some point, have ignored the satnav. You’re sure you know a quicker way home. The screen says go right, but you’ve spotted what looks like a clever shortcut. So you take it. And ten minutes later, you’re stuck behind a refuse lorry on a single-track lane while your dinner goes cold.
The satnav doesn’t know more than you do, exactly. It just doesn’t have hunches. It works from data. Over thousands of journeys, its systematic route beats the driver who relies on instinct.
A similar pattern holds in finance. Evidence-based investing is the financial equivalent of the satnav. Not glamorous, not exciting, but systematically more reliable than the alternatives over the long haul. Most people’s money, however, isn’t managed that way. A professional says they know which stocks to pick, when to buy, when to sell. It sounds like expertise. But what does the evidence say about how well that approach works?
Matt Kiddle, founder of rockwealth Harrogate, starts from a simple premise: ‘The most important thing about an investment philosophy is that you have one. And preferably it’s an evidence-based one.’
The numbers most fund managers would rather you didn’t see
The data on professionally managed funds is unambiguous, and it’s been unambiguous for a long time.
According to the most recent SPIVA Europe Scorecard, covering the year to December 2025, 88 per cent of broad UK equity funds failed to beat their benchmark. Among UK small-cap funds, the figure was 97 per cent. SPIVA has been tracking active fund performance for more than two decades, and in country after country, year after year, the same picture appears.
Ben Felix, a Canadian portfolio manager and one of the most-watched financial educators on YouTube, put it bluntly in a recent episode of The Diary of a CEO podcast: ‘If you look at the data on professional money managers who are trying to beat the market, most of them don’t. And the ones that do don’t tend to go on to beat the market in the future.’
That last point matters. SPIVA’s persistence scorecards show that the winners rotate. If you’d picked the best-performing UK equity fund five years ago, the odds it would still be a top-quartile performer today would be little better than a coin toss.
If the data feels too abstract, consider Warren Buffett’s famous bet. In 2008, he wagered $1 million that a simple S&P 500 index fund would beat any portfolio of hedge funds over the following decade. Ted Seides of Protégé Partners picked five funds-of-funds, between them holding more than 200 underlying hedge funds. Over the decade ending 31 December 2017, the index fund returned 7.1 per cent a year. Seides’ selection returned 2.2 per cent. It wasn’t close.
Why beating the market is so hard, and why that’s good news
The reason most active managers fail isn’t that they’re stupid or lazy. It’s mathematics. Before costs, the average return earned by actively managed money must equal the average return earned by passively managed money, because together they make up the entire market. For every active manager who beats the market, another must underperform by the same amount. After you subtract higher fees, the average actively managed pound delivers less than the average passively managed pound. Not most of the time. Always.
Kiddle reaches the same conclusion from his own seat: ‘The evidence has shown us that the traditional active way of running money, taking tactical approaches to stock selection or market timing, doesn’t actually deliver a return over and above what would otherwise be returned by the market. So the fee that gets paid for that service is not rewarded with the returns that are promised.’
Here’s why that’s good news. You don’t need to find the next genius fund manager. You don’t need to predict the next market crash. The market itself, over time, has rewarded patient investors with healthy returns. You just have to participate in it efficiently.
Felix offers thematic ETFs as an example of complexity dressed up as opportunity. ‘What tends to happen with thematic ETFs is that something becomes really hot. Asset prices go up because there’s a lot of interest. An ETF gets launched when asset prices are up here, and then the prices come down. The returns on thematic funds tend to be very poor.’
What evidence-based investing looks like in practice
Evidence-based investing means owning the whole market at relatively low cost, and then having the patience to leave the portfolio alone.
Kiddle puts it like this: ‘An evidence-based approach starts from the position that the markets will deliver us all the return we need. We just have to have an efficient way to go and get hold of it. As part of that, keeping costs really low is a fundamental pillar.’
In practical terms, that usually means a portfolio built from globally diversified and broadly passive funds. You own thousands of companies across dozens of countries. You don’t try to pick which ones will do best. You accept the market’s return and let compounding do the heavy lifting over decades.
There’s a counter-intuitive truth at the heart of this. As Felix puts it: ‘People who know just enough, they know that index funds are sensible and they have enough conviction to stick with that, will be better long-term investors than someone who knows enough to hurt themselves.’
The cost piece matters more than most investors realise. A worked example brings the point home. Take a £500,000 portfolio growing at 5 per cent a year in real terms before charges, and run it for 20 years. With an annual cost of 0.3 per cent, the pot grows to roughly £1.25 million. With an annual cost of 1.5 per cent, it grows to roughly £995,000. The difference is around £258,000. (These figures are illustrative, assume reinvested returns and constant charges, and are not a guide to future outcomes.)
Felix offers reassurance on the hardest part, sticking with the approach when markets misbehave: ‘The world has been through a lot of crazy stuff, wars, turmoil, political upheavals. And we’ve come out okay in general. Stock returns have been positive despite all the craziness. Someone who’s globally diversified doesn’t have to make changes to their portfolio when the world’s getting crazy.’
The real value a good financial planner adds
If evidence-based investing is simple, the question becomes what a financial planner is for. The answer is almost everything except picking stocks.
Felix is direct about it: ‘You can’t control markets, you can’t control your performance relative to the market, and trying to outperform tends to make you worse off rather than better. But the things that you can control, having an appropriate financial plan, having the right goals, having an asset allocation that makes sense for you, tax planning, those are things you can control.’
This is where strategic financial planning earns its keep. Cashflow modelling, in particular, can be transformative. Kiddle finds the conversation often surprises clients. ‘What we find sometimes is people are already through the finish line. They’re still turning up to work every day thinking they’ve got to build a bigger and bigger pot.’
That’s not a small insight. It’s the difference between retiring at 67 because you have to and retiring at 60 because you can.
Behavioural coaching matters too. Vanguard’s UK research, Quantifying Adviser’s Alpha, argues that holding clients steady through downturns adds, on average, around 1.5 per cent a year in net returns compared with what those investors would earn on their own. The figure is an estimate, not a guaranteed outcome. But the principle is well established: the biggest single source of underperformance for most retail investors is their own behaviour.
Then there are fixed fees. A percentage-of-assets fee model means that as your portfolio grows, the cost of advice grows with it, even when the work doesn’t. A fixed-fee model keeps that relationship transparent and removes the conflict of interest baked into traditional charging structures.
Letting the satnav do the driving
The simplest investment approach has the strongest evidence behind it. The hardest part isn’t picking the right funds. It’s staying in the car.
A good financial planner isn’t the driver who overrides the satnav. They’re the calm voice in the passenger seat, talking you out of taking a random exit when the traffic’s bad and your patience has run out.
Kiddle puts the goal in human terms: ‘Seeing people deliver more of those things that are important about their lives to themselves, and helping them align their finances to deliver that.’
If you’d like to explore what an evidence-based approach could mean for your own finances, Matt Kiddle at rockwealth Harrogate would be happy to have a conversation.