Pension drawdown forecast spreadsheet

Justso65

I think the main things about these discussions are the contributor's are looking at projections and investment returns.  Many people I know wouldn’t consider looking at these aspects and will probably just hope/pray their pension is enough to see them out.

gm0

As you move on to "what asset mix to hold" to achieve estimated growth. 
And to "how shall I access the money and implement any buffering". 

Then after the Lars type of spreadsheet. 

Perhaps go to amazon and purchase "Living off your Money" by Michael McClung who has done a lot of the access method and high level portfolio shape testing stuff.  Also you can give the lengthy ERN drawdown blog series a read.  Backtesting and MC simulation for days.

The conclusion is that most methods can work.  Some are oversimplified and work a bit less well.
But there are some marginal gains to withdrawal rate (or risk reduction at the same rate) which push you to choose approaches X,Y,Z over approaches A,B,C.  Gains which don't disappear when you replace the US data series with other international market data sets.  Some complexity is added for some methods.

Neither backtesting nor random simulation (MC) of returns will convince those who say that - future market behaviour is unknown and may be outside the past or your simulated envelope - so this is all rubbish (not predictive).  They then typically fail to offer any helpful alternative supported by evidence whatsoever.  And this approach is indeed better than nothing to support planning.

Backtesting and MC sim can't and doesn't mathematically prove the positive about an unknown future.  But it does helpfully elmininate terrible ideas which "would have already failed to work" in those past or simulated markets.  That it can do. Compare X to Y within a given envelope.  I am not about to adopt a strategy that demonstrably has already failed to work on the off chance that future markets conspire to a very specific behaviour that would reverse that.  I'd rather have a strategy that already works most of the time.  And continues to behave airthmetically unsurprisingly when hit with stressed market simulation.

Actual portfolio design and specific fund selection follows on.

Which can be relatively simple or the hardest element for the novice investor. 

If you have bought the passive indexer cheaply line then it's fairly easy - cheapest reputable large liquid fund on your platform
If you are building your own portfolio from smaller sector + country blocks it's more tricky.