I think Ursula Downs is an awesome investigator worthy of a lengthy data driven review. In case "lengthy" is'nt your cup of tea, here's the TL:DR:

Ursula Downs is one of the fastest investigators in the game and she's reasonably survivable thanks to her high . She is let down by her minuscule cardpool but just bring all the clue cards and focus on the clues.

.......................................................................................................

First off, stats!

• 3 makes Ursula squarely middle of the road, defending against will be important to her since her weakness forces horror damage, give consideration to Logical Reasoning, Elder Sign Amulet and/or Tooth of Eztli and obviously: Guts.

• 4 is to be expected, it may take some work to make "I've got a plan!" hit but with the proper assets and allies clues will not be an issue. Because of Ursulas speed seriously consider Fieldwork in your base deck as a means to consistently finish difficult locations, this only gets better on higher difficulty and if you play Archaic Glyphs.

• 1 is to be ignored. Even Swarm of Rats is better evaded then fought.

• 4 means that the vast majority of enemies don't pose you real danger, it does mean that multi-clue pickup is extra important though so that you don't spend too much time hanging around a location with evaded enemies on it. This stat lineup also benefits unusually well from Hyperawareness. Sadly there is literally nothing in your cardpool that leverages into anything useful (aside from evaded enemies).

So, Ursula has a very single-minded stat set, GET ALL THE CLUES, EVADE ALL THE ENEMIES. Looking at her health and sanity you might think she wont ever die, Health will not be an issue, but horror can get very dangerous, resist it!

Her ability requires little discussion, free investigates! Keep in mind that you may use the free action to trigger your Investigate assets (Fingerprint Kit, Archaic Glyphs) and other Investigate effects. If you have Shortcut+Pathfinder or 2xPathfinder you can use all the free movement to shuffle around and net free investigates anywhere you like. Ursulas ability nets her more investigate checks per turn which makes Arcane Insight a good pick for her.

The ability is really nice, but not always helpful, you sometimes just don't want to move. A +1 with an optional bonus is still much better then a scaling bonus with no extra effect so Ursula has it pretty good in this case.

.......................................................................................................

So, cardpool. Short version, she's a straight , long version, the ability to grab artifacts is extremely limited. At level 0 the major options are The Chthonian Stone and... stuff you really don't want.... At higher levels it looks a little nicer, Charon's Obol for the risk-taker, Lucky Dice for consistency, The Gold Pocket Watch is one of the most powerful effects in the game, Grotesque Statue is another consistency route. So yeah, the XP options are interesting but still few in number, Ursula Downs has one of the smallest cardpools but look on the bright side, its bigger then Mateo's.

With her nice Ornate Bow might grab your attention, just keep in mind that there is no card support here, no Live and Learn, Lucky!, Streetwise, Narrow Escape, Double or Nothing, Leo De Luca, Quick Thinking you get the picture. There is still Hyperawareness so you can still muster accurate shots, but it will come at the cost of your Magnifying Glass and/or Fingerprint Kit. I'm obviously not a fan of this setup but if you're super desperate for a way to fight then this is it.

Ursula Downs lover her the classic go-to clue stuff, everything that grabs extra clues, boosts and buffs. Dr. Milan Christopher, Magnifying Glass, Deduction, Fingerprint Kit. Another important thing for Ursula is speed, Working a Hunch so that she doesn't spend too much time on a location after evading, Shortcut and Pathfinder are musts, Fieldwork and/or Arcane Insight to put all this speed to use, the high movement also gives extra strategic value to Connect the Dots since you can easily leverage Pathfinder to browse locations to make the combo happen.

Ursula Downs likes her some Archaic Glyphs, both options sync with what she does so with/without Shrewd Analysis risks you'll always get stuff you want, I prefer the bonus clues though.

Strange Solution however is a bit less useful for her, her only way to buff a Strange Solution attack is with Unexpected Courage, so accuracy is an issue, the Strange Solution isn't needed and she doesn't have time to spend her actions supporting the team with Strange Solution. I'dd say Strange Solution is still worth the work if you're desperate for more killing power but leave it on the shelf in 3 player.

Defensively you can ponder Trench Coat and/or Tooth of Eztli.

.......................................................................................................

Finally, the signature cards.

Jake Williams is'nt terribly helpful. Extra cards are nice but this has an upper limit on how often it may trigger and contests the ally slot for Dr. Milan Christopher, you might grab an extra buddy like Dr. William T. Maleson and go for Charisma but generally I just play Dr. Milan Christopher whether or not I'll bediscarding Jake Williams to do so, > Card draw.

The weakness, Call of the Unknown, woo this one is nasty. Luckily if you draw this early you'll only be slightly more desperate to do things you want to anyway, move forward and get clues, as the game progresses less locations will have clues, you may still investigate a location with no clues but this will still suck away your movement advantage and free clue pickup on a roundly basis. Try to resist horror the best you can so that you might take this on the chin every now and then.

.......................................................................................................

Altogether. Ursula Downs will probably take more investigate checks per map then any other character, with an effective of 5-7, she can not quite match Rex Murphy clue for clue but the race is still very close, and she's a heck of a lot safer then he can be. Her ability to kill stuff ranks among the worst in the entire game so partner with friends who can cover that aspect and bring "I've got a plan!" to relieve the pressure against the worst encounter enemies and bosses.

Frankly speaking, I do not think this is among the best of cards.

• The risk. Drawing just one, two, or no cards if you draw a bad token.
• The actions. An action to play and more actions to use. The net gain is very fast on good token draws, but you're still depending on luck! I find 3 draws at 5 a rather stable result on standard.

There's also a resource cost but as a you don't care about that much.

So, when is it good?

................................................................................................

Not for every Daisy Walker, she's busy with her Old Book of Lore, the arcane slot also has lots more competition. It might be worth a shot once the book turns into Encyclopedia, but that's often very far down the line.

Not for Norman Withers, obviously.

Rex Murphy can put it to use, you can definitely build a deck with it to quickly draw all the tools and support to keep you moving and clue-ing. But be aware that you'll see a lot more of his weakness.

Ursula Downs can use it too, but again in a fairly "alternative" kind of way, just to draw her deck faster and find the movement assets, the plan more consistently.

And finally, in my opinion where this card is at its finest, Minh Thi Phan. Minh likes skill cards, she likes Cornered to work around the weakness and to use with Strange Solution, Cornered + Strange Solution means that she fights at +8, very nice for a , and Feed the Mind fuels it with cards to discard.

.........................................................................................................................................................

So, at the moment, a utility card that's just got one proper deck where it really really shines. Try it. I recommend it.

This card is underrated. Imagine a fast 1-cost guardian card that gives +2 combat and +2 agility until the end of the investigator's turn. That would be an auto-include in many combat-focused decks. So why is this card so little valued when it basically does that (at least against one enemy)?

I’m having a bit of a hard time quantifying the strength of this effect. It seems like it has about a 50% chance of combining a bad token draw with a good one, thus giving you a great choice. Two good tokens or two bad ones drawn together is not as helpful. Also it seems to be better on higher difficulties, where the difference between good and bad tokens is larger. But I think the card might be a bit overrated because of the high XP and the significant chance of drawing two similar tokens.

Four reviews for Joe and none for Carolyn, the most interesting investigator in the game? This will not stand.

The Combat Medic

Carolyn Fern is an especially durable Guardian with a powerful ability and effect. Additionally, her deckbuilding options are extremely broad, enabling great flexibility in her builds. This is both a blessing and a curse (appropriately), as one can feel inundated with decisions and suffer from option paralysis. Additionally, the devs seem to value flexibility very highly when creating characters, resulting in Carolyn having a base stat total of only 11. Her increased durability (she has an extra point in health/sanity) offsets this, but I would say a stat point is more valuable than health/sanity, so it's a bit meh.

What Makes Her Great

Carolyn's deckbuilding options combined with her ability open up a massive array of options that totally warp how a player should value cards. What do I mean by this exactly? Take First Aid, a fairly lackluster card that few Guardians can find room for. In Carolyn's hands, it can not only bring an ally from the brink of insanity but also allow them to afford their expensive assets. Clarity of Mind becomes a similar tool for both saving and paying allies, despite being maybe the worst horror heal in the game overall. Once higher level cards become available the the player, one's options expand into truly ridiculous healing tools like First Aid(3) and Ancient Stone(Minds in Harmony). On the other hand, those two items are basically the only high-level horror heals that your allies will care about.

A sidebar on Ancient Stone: With Shrewd Analysis, one can upgrade two copies into Ancient Stone (Minds in Harmony) for only 3xp. This is well worth one / slot, especially since the stones free up their slots after being upgraded. Identifying it can be tricky without devotion to clue-gathering, but shooting for a total of 4+ is very strong, since it neatly counters Rational Thought.

Basically, Carolyn fundamentally alters the value of many sub-par cards, increasing the amount of viable includes while deckbuilding.

Core Builds

Carolyn has so many options that it can be helpful to focus on a strategy and include some core elements, filling out the rest of the deck as one sees fit. To that end, here are some effective cores:

Cluever

Dr. Milan Christopher
Alyssa Graham
Magnifying Glass
St. Hubert's Key
Deduction
This is a build with very strong static increases to investigation. With everything in play (which ostensibly includes Charisma, a superstar include for Carolyn) the investigator is up to 8 while investigating. This would require a massive amount of resources, but I have done it. It also makes identifying the stones fairly easy.

Support

First Aid
Clarity of Mind
Liquid Courage
Inspiring Presence
With these assets Carolyn is able to bankroll her allies, feeding money to the fighter so they can afford their expensive weapons. With xp, Stand Together is an incredible value both xp and card-wise. Inspiring presence can also be used to heal and recharge your own or your allies' Beat Cops.

Combat

Guard Dog
Beat Cop
Shrivelling
"I've got a plan!"
Dynamite Blast
This build uses guaranteed damage to deal with enemies and Carolyn's tankiness and healing to soak shots. Between her ability, Stick to the Plan and Emergency Cache, she has consistent access to guaranteed burst damage, despite it being fairly resource/xp intensive. In any case, "I've got a plan!" is and has always been a very strong outlet for damage, despite its one-shot nature, and I feel Shriveling would need a lot of support (from St. Hubert's Key/Holy Rosary, Arcane Studies, and/or Peter Sylvestre(2)) to be effective late-campaign.

Other Strong Cards for Carolyn

Peter Sylvestre
The big man on campus can provide you with a constant stream of resources, while providing his static stat boosts and infinite horror soak as usual. Combined with a reliable way to take horror, Peter becomes an enormous economy card rivaling Dr. Milan Christopher. Speaking of which...
Forbidden Knowledge
With Carolyn's ability to heal horror, this is very safe to take. If Peter Sylvestre is in play, you double your resource gain and take no horror, which is quite strong. Cautious players (or those on higher difficulties) might opt for Painkillers instead, since it can provide fast, reliable horror in much the same way while shoring up Carolyn's low health.
Charisma
In every Carolyn deck I've ever built, I've ended up with more than four ally cards. Especially if you decide to go with Foolishness, one or even two copies of Charisma will enable Carolyn to maintain powerful effects on the board, such as Dr. Milan Christopher and Peter Sylvestre, or Alyssa Graham and Dr. Henry Armitage, or Foolishness and Peter Sylvestre. Her allies are incredibly useful.
Ever Vigilant
Similar to Charisma, Ever Vigilant allows Carolyn to setup for the whole game in a single action. I prefer assets over events for horror heal, so every deck I build with Carolyn has more than 20 assets. In this case, Ever Vigilant is incredibly strong and will likely be useful even late in the game, especially if you've found yourself without actions to play cards and great assets building up in your hand. This can also go under Stick to the Plan, although Carolyn doesn't have quite as many viable options for that card, so it might be overkill. I think taking aggressive mulligans for Ever Vigilant is probably the better strat, as it saves you 6xp.

The most effective strategy is probably to combine two of these cores into a deck that can take useful actions at any point in the game, for example by combining the Cluever with the Support suite. Or one can be more adventurous and combine everything they think is cool into some kind of monster. The options are quite vast.

Signature Cards and Weaknesses

Hypnotic Therapy is a very good card. Being able to heal one horror from any investigator every turn for the rest of the game is ridiculous, and it draws that investigator a card, and you can give them a dollar with your ability. If this is the only horror heal you get in play, things start to stabilize instantly. If you get it into play later, it's a steroid for your other horror heals, so that's great too. I wish it didn't exhaust for both effects, but it would definitely be broken if that were the case. Rational Thought, her corresponding weakness, isn't nearly as bad as To Fight the Black Wind, especially with Hypnotic Therapy or Ancient Stone (Minds in Harmony) with four secrets on it in play. It is still very annoying, since you don't get the benefit of your ability while it's out, so it can hurt your income. In my experience, it hasn't affected me at all, but I have yet to draw it when we're all about to go insane and I'm low on healing options. In any case, Alyssa Graham is useful to avoid such occasions.

Foolishness, her replacement signature, is very good, but also very annoying. Aside from needing a bunch of support to come online (which, admittedly, pays you back a bit), he also takes the ally slot, which is so incredibly valuable. I think he becomes more attractive in a four-person party where other investigators need Dr. Milan Christopher or Peter Sylvestre more than you do. To Fight the Black Wind, the corresponding weakness, is extremely terrible and can result in the agenda flipping a turn early if drawn in the upkeep phase. Ancient Stone (Minds in Harmony) is also very good against it, as long as you draw it with some actions to spare. There's certainly an argument to be made for taking all of her signature cards, since they do have some synergy with each other, but it is resource intensive.

Conclusion

Carolyn is one of my favorite investigators, probably for the same reasons that many seem uninterested in her: she's super weird. Her versatility is incredible, her ability is interesting and strong, and has no phase/turn limit, and her stats are strong enough that she's a competent investigator before applying any bonuses. Still, she has her downfalls: I've frequently found myself in scenarios with no horror to heal, which makes me value Forbidden Knowledge a little more highly. Her effectiveness is also highly campaign-dependent, I feel; she has plenty of horror to heal in NotZ and Carcosa, but less to do in Dunwich. In Forgotten Age, I think she's downright bad because the campaign throws far more damage at one than horror and her is garbage. With its focus on "the ethereal," I'm going to assume the Circle is also heavy on horror, so she might function quite well there (investigators are generally pretty powerful in their release campaigns).

Anyway, I hope you've enjoyed this review of Carolyn Fern. Thanks for reading.

Edits:
Carolyn can't take Monster Slayer; I'm an idiot. Good catch @Death by Chocolate.
Added Dynamite Blast in the Combat build; she's one of the few s who can afford it, and I forget how good it is; good call @Swekyde.