# What makes an estimate “conservative?”

When estimating (time, for example), it's common to either ask for or offer a "conservative" estimate. Irrespective of political connotations, how does "conservative" describe a given estimate?

Is a conservative estimate the one the causes the least disruption, regardless of whether the estimate is an overestimate or an underestimate?

• ...or "liberal" for that matter. – mHurley Jun 17 '16 at 16:08
• In such contexts, conservative means something more like cautious, non-optimistic. Which usually means any scalar value cited in a conservative estimate is likely to be lower than most other estimates. But presumably there can be contexts where the conservative approach leads to a higher estimated value for something than other predictions. – FumbleFingers Jun 17 '16 at 16:19
• ^^ this is the best answer so far ;-) – mHurley Jun 17 '16 at 16:29
• Yes to what @FumbleFingers said, and will add that the reason as estimate would want to be "conservative" is usually so the recipient of the estimate would be prepared for a "worst case scenario". (The numeric swing and direction of what conservative means is totally contextual to the thing being discussed.) – ben Jun 17 '16 at 16:31
• A conservative estimate protects (or conserves) your side's bottom line or reputation for execution. – user662852 Jun 17 '16 at 16:40

The dictionary definition of 'conservative estimate' is one which is deliberately intended to be lower than what the real value actually is.

In the case you mention, where a high estimate is the one that involves the least risk, you could reasonably argue for describing it as conservative, but you will be going against established usage and run the risk of being misunderstood. I would recommend looking for another word in this case - perhaps 'safe'.

• I'm not looking for a particular word. I'm looking to understand this one. It's difficult to conclude because the OED says: "Characterized by caution or moderation; (esp. of an estimate) purposely low for the sake of caution." So I'm trying to work out if it's the smallness that makes it conservative, or the caution that makes it conservative. – mHurley Jun 17 '16 at 17:18
• If you ask me how long it will take me too build a shed and I think it will take 1 week, so I tell you 2 weeks - that seems like a conservative estimate to me. – Laconic Droid Mar 14 '17 at 16:54

What FF said -- a conservative estimate is the least risky, given whatever criteria for "risk" exist. As such, it may be less apt to "grab opportunity".

Eg, if I'm operating a Christmas tree lot I generally need to order all of the trees from the tree farm before the season starts, and before I have a good idea of what the market for trees will be this year. A conservative estimate of potential sales would leave my lot empty at the end of the season (lost opportunity) while a liberal estimate would leave me with unsold trees at the end (with actual money lost since I still must pay the supplier for those trees).

A conservative estimate is a 'guess' on the lower side of given parameters, based on knowledge and experience. I'll use the analogy of an auction valuation. If the valuer believes the item in question may achieve a bid of between, let's say 10k to 15k, the conservative end of his valuation is 10k. The item may, if the right under bidder is present achieve much more, or, maybe not even reach it's reserve. It's an estimate. I reiterate, a conservative estimate is a 'guess' based on knowledge and experience

• I don't agree that "a conservative estimate is a 'guess' based on knowledge and experience". – user140086 Jun 17 '16 at 17:50

I would say that a "conservative" estimate means the absolute minimum number a quantity could be.

A "liberal" estimate would be the maximum quantity if you factored in every assumption that could potentially increase it.

I think an example might be, if you are counting widgits, and there were some things that might be widgits or might not, a conservative estimate would exclude them, and a liberal estimate would include them.

To be conservative with an estimate is to wish to avoid underestimating, while to be liberal is to want to avoid overestimating.

So, if you were in a position of giving an estimate, you look at the consequences of underestimating or overestimating. For example if you were an employee of a company, and your boss says "How long will it take you to do X?", you might think:

"If i underestimate the necessary time, i'm going to end up delivering it late, and look bad. On the other hand, if I overestimate the time my boss will probably just say "Ok" and put that in the planning schedule, then later I get to deliver it earlier than expected and look cool."

So, there's bad consequences for underestimating, and no bad consequences for overestimating. So, you would overestimate, and you would call that a conservative estimate.

If you were a freelancer, there's also potentially bad consequences for overestimating: they might give the job to someone cheaper. So, you need to balance the two potential problems. If you were really desperate for the work, and willing to take a risk on having to work nights or something, you might give a liberal estimate - a cheap one in this case.

So, logically, a conservative estimate is one where you deliberately overestimate the resources (time, money, materials etc), and a liberal estimate is one where you deliberately underestimate the resources (perhaps because you think it's going to be easy, and you want to make sure the client gives you the job).

• I could accept the statement that "To be conservative...is to...avoid underestimating" but I'm not sure about the explanation. Is a "conservative" estimate conservative because there are fewer bad consequences for it? Therefore, if UNDERestimating had the least-negative consequences, would it become the "conservative" estimate? I'm just not sure I follow the explanation well... – mHurley Jun 17 '16 at 16:28
• I've never heard of a "liberal estimate". The reverse of a conservative estimate could be an "aggressive estimate", "stretch goal" or similar marker that the estimate has a risk of not being met. – user662852 Jun 17 '16 at 16:36
• A conservative estimate is usually a low one, i.e. one that wants to avoid overestimating. ldoceonline.com/dictionary/conservative_1 – DJClayworth Jun 17 '16 at 16:45
• The truth is that, at a conservative estimate, there are only about eighty thousand South Asian nationals (in Kenya). It seems pretty clear the writer there suspects the true value is in fact lower than his conservative estimate. – FumbleFingers Jun 17 '16 at 17:12
• @mHurley A conservative estimate is one where you deliberately, knowingly overestimate. The stuff about consequences just explains the motivation for the decision to make a conservative estimate. – Max Williams Jun 20 '16 at 7:28

Conservative

Adj - Less risky (conservative estimate), Less wasteful (conservative consumption) Noun - A person disposed to conservative actions / choices.

• Can you expand on the dictionary lookup to help the requestor? – Yosef Baskin Mar 14 '17 at 15:13