Fallout: New Vegas Reputation

Reputation in Fallout: New Vegas is a way to measure general feeling for your character in each principal towns and factions like Fallout 2, and will even give you access to new areas in the game.

Reputation can be modified by doing good or bad deeds, like completing quests or killing townsfolk or member of a faction. Your reputation with any given group is a measure of the combined total of Fame and Infamy that you have earned. The benefits and drawbacks of any given reputation depend of the group itself. You may receive discounts with merchants, provoke attacks from hired thugs, or simply be treated differently.

You can also equip faction clothing (e.g. NCR uniform) to impersonate a member of the faction the clothing belongs to, and will be considered one of them, meaning your reputation with the respective faction will be "neutral", regardless of their actual disposition towards you (i.e. a "vilified" reputation will turn into "neutral", as will a "Idolized" reputation, with all drawbacks a lower reputation brings!). Note that such a disguise will only work on common members of that faction and that officers, security guards and dogs will be able to see through it. Also, any member of a faction with a negative disposition towards the faction whose clothing you wear will attack you on sight as your true reputation with that faction will be ignored as long as you are disguised.

Reputation
There are two different scales of reputation (denoted 1 and 0 in the console), earned by doing helpful or harmful deeds, respectively, to the faction. The combined effects of the two scales result in an overall reputation that is either positive, neutral, or negative. In the table below, these are colored green, black, and red respectively.

Note that at this time there is no known way to erase past deeds(however you can start rumours in freeside that affect your reputation, just visit atomic wrangler citation needed). Your scores in the two scales only accumulate - neither ever goes down. In other words, while it's possible to move from 'Hated' to 'Sneering Punk', then 'Unpredictable', then 'Dark Hero' by doing more and more good deeds while avoiding bad ones, there's no way to move from 'Hated' back to 'Neutral' or from 'Hated' to 'Idolized.' Similarly, once a reputation of 'Wild Child' is earned, there's no ability to change it at all. However, two specific story events will erase negative reputation you have gained with the NCR or Caesar's Legion.

When disguised, none of your typical reputation levels apply. This is reflected in the absence of reputations in your PipBoy. However, certain NPCs, particularly guards, may see through your disguise and attack you if you are Vilified with their faction and are standing in close proximity.

Faction reputation
Certain major factions, such as the NCR or Caesar's Legion, will dispatch troops as you wander throughout the wasteland.

If you gain positive reputation with the NCR, they will send a trooper to give you an emergency two-way radio, which you can utilize for reinforcements or supplies while in good standings with the Republic. However, a negative reputation will reward you with a warning from an NCR Ranger accompanied by two troopers, who will grant you a three-day grace period to remove the negative status, or will fight you immediately if you challenge them in the dialogue. If you are unable to remove the negative status before the alloted time (assuming you didn't already fight them), the Ranger and company will appear again, automatically open up dialogue, and then become hostile (series of events was obtained while as a "merciful thug". Needs further confirmation.)

Caesar's Legion is not as forgiving as the NCR. There is no grace period, but the automatic dialogue will occur. The Legion's forces contain a Vexillarius, two Legionary Assassins, and two Recruit Legionaries; all of them well armored. (series of events was obtained as "hated" by the Legion. Needs further confirmation.)

These parties can be seen advancing towards your direction, so you can start firing at them pre-emptively. This will cancel out the formalities of a dialogue and the troops will immediately become hostile. The only way to avoid such confrontations is to maintain a level of reputation that is neutral (or neutral-like, such as mixed) or better. Also note that while you are within the borders of a populated area such as a town or while inside a location such as a vault or building, these confrontations will not happen; if that town just happens to be a faction you are not in good standings with, the NPC's within the town will still act accordingly based on your level of reputation. The troops will only appear while you are traversing the wasteland. However, when exiting a place such as a vault or building that is outside a heavily populated area, these troops may be right outside, and will confront you immediately upon your exit.

Killing these troops will also add more infamy towards that faction. There is no way to talk them out of fighting.

Towns reputation
A town's reputation determines your treatment by the townsfolk.

A positive reputation may yield positive dialogue, discounts from vendors, and even free gifts from wandering citizens. A negative reputation may result in negative attitudes by the citizens and higher prices when trading.

Bugs
It is possible that the game doesn't register taking off faction armor properly when switching directly to another piece of armor. In that case your PipBoy will still show your reputations as if you were wearing faction armor. This may lead to confusion when the player is being attacked by previously friendly factions. Putting on any kind of faction armor and taking it off again usually restores the players faction standing.