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by GlennS 1496 days ago
> This is true despite the fact that you know exactly when the market will hit a bottom. Even God couldn’t beat dollar-cost averaging.

I'm a bit unconvinced by the studies that say this, because I don't think the "buy the dip" strategy they're talking about is the same one that people are running.

The studies describe waiting for a low point in a given year (or even across multiple years!) then lumping in all your money then.

Whereas I think what people actually mean when they talk about buying the dip is shifting their dollar cost averaging buy-in by days, weeks, or at most a few months, while they wait for the market to get spooked.

I don't do this at the moment. I had a "wait for the US president to say something stupid" strategy which seemed to work for a while, but of course I don't really have enough evidence to back that up.

2 comments

Even an investor who just waited for 5% or 10% dips would have underperformed an investor who bought on a fixed schedule each month, historically:

https://www.bogleheads.org/forum/viewtopic.php?p=6196749#p61...

But even if you're just modifying a DCA schedule slightly (buying a little early/more when things feel particularly cheap, or buying a little later/less when things feel expensive) -- doesn't the same problem exist: that those adjustments typically cause a worse outcome than if you didn't apply them?

Maybe some people have a better crystal ball than others, but if we just look at the average case where studies favor vanilla DCA, I have to imagine that the reasons (why DCA wins) will prevail regardless of the extent that they're applied. But if your skill is enough above average that it's helpful to deviate, go for it...