Where does proxy collide?

In econometrics a proxy is an observable variable used in place of an unobservable one, such as schooling standing in for ability, so a model can be estimated at all. The construct is a deliberate substitution whose cost is bias: how well the proxy tracks the latent quantity determines whether its use reduces or worsens the error relative to simply omitting it. McCallum's 1972 Relative asymptotic bias from errors of omission and measurement compared these two biases and showed when a noisy proxy is still worth including. This is a stand-in measurement, unrelated to a network relay, a climate archive, or a bid left with an auctioneer.[1]

Unit

The association between the proxy and the latent variable it represents

Recovery means

Not applicable

Measured by

Judged by the bias and residual error introduced when the proxy replaces the unobserved variable

In networking a proxy is an intermediary server that receives a client's requests and forwards them to origin servers, returning the responses, so it can cache content, enforce access control, or bridge firewalls. The construct is a stand-in endpoint that speaks for the client, decoupling it from the servers it ultimately reaches. Luotonen and Altis's 1994 World-Wide Web proxies described the design of such a forwarding, caching intermediary for the early web. This is a software relay, not a substitute statistic, a sediment record, or an absentee's standing bid.[2]

Unit

Requests mediated, with cache hit rate and added latency

Recovery means

Not applicable

Measured by

Assessed by throughput, cache hit ratio, and the latency the intermediary adds or saves

In auctions a proxy bid is a maximum left by a buyer who is not present, which the house or platform raises on their behalf by the minimum increment only as far as competition requires, up to that limit. The construct is delegated, automated bidding that represents an absent bidder's true ceiling without revealing it at once. Roth and Ockenfels's 2002 Last-minute bidding and the rules for ending second-price auctions analysed how eBay's proxy-bidding system interacts with bidder behaviour and closing rules. This is a standing instruction to bid, not a statistical stand-in, a network relay, or a geological archive.[3]

Unit

The maximum bid the agent will execute on the absent bidder's behalf

Recovery means

Not applicable

Measured by

Observed through the submitted maximum, the increments executed, and the timing of bids

In paleoclimatology a proxy is a measurable feature of a natural archive, such as tree-ring width, ice-core isotopes, or coral bands, that stands in for a climate variable not directly recorded before instruments existed. The construct is an indirect indicator whose value must be calibrated against modern observations before past temperature or precipitation can be inferred. Bradley's Paleoclimatology: Reconstructing climates of the Quaternary surveys these proxies and the methods for reading them. This is an environmental stand-in preserved in nature, unrelated to a regression variable, a network server, or an absentee's bid.[4]

Unit

The calibrated relationship between the measured indicator and the past climate variable

Recovery means

Not applicable

Measured by

Established by calibrating the proxy against instrumental records and quantifying reconstruction uncertainty

In international relations, proxy refers to proxy war, in which an outside power supports a party to a conflict instead of fighting directly itself. This meaning comes from Mumford (2013) in Proxy Warfare.[5]

Unit

Recovery means

Measured by