I would become familiar with
pot odds and
equity of various
hands a long with ranging opponents if you want to make your decision making in this spot easier and profitable in the long term.
For example, The blinds are 2k 4k with Ante 500. You have 170,000. Short Stack has 21000.
If the player has been playing loose or recently lost a few big pots you can predict his range to shove here as being lose. His position is also important as he will be shoving tighter in EP. If the player has been playing tight as a rock, blinding down and only ever showing premium hands you can presume his range here will still be tight. For the sake of this example lets say the loose player is shipping the top 20% of hands here and the tight player perhaps the top 10%.
Top 10% range looks like:
88+,A9s+,KTs+,QTs+,AJo+,KQo
Top 20% range looks like:
66+,A4s+,K8s+,Q9s+,J9s+,T9s,A9o+,KTo+,QTo+,JTo
Now with 9 players in the pot that puts 4.5k in antes plus the blinds of 6k, so 10.5K total. When villain ships for 21k in this spot from a position not in the blinds you are getting odds of 1.5:1(ish) or 60/40.
This means that if your hand has a 40% chance of winning then the call is mathematically correct. A hand such as K5s has these odds against a 20% range or ATs against a 10%.
From the BB you get even better odds as you already have 4k invested. So you only need call 17K to win 31.5k, not far off 2:1, meaning you only need 33%. An example would be J9o against a 20% range and K8s against a 10% range.
The careful thing to note here however is that this MATHEMATICALLY correct only. It does not take into consideration other players left to act behind you, table dynamic, player differences, pay jumps, tournament stage etc so may not be the OPTIMUM play in a specific situation.
However by familiarising yourself with this sort of concept there are spots where you can correctly call all in shoves with cards that may at first glance appear very light, this can be especially useful in turbo tournaments where the need to take risk is increased, especially as the blind levels increase. Using other tools such as fold equity and table image can also be beneficial here, along with playing close attention to other stack sizes at the table.
I tried to explain this briefly as best I could to demonstrate the concept. You may find it beneficial to download a programme called pokerstove to familiarise yourself with these sorts of ranges and equity.