The recurring character Ariadne Oliver (present in a number of Agatha Christie's novels) seems to be at least partially self-insertion by Christie. At the very least, both write mystery fiction stories featuring a foreign detective. Besides this superficial resemblance, how much does she actually resemble Christie herself?
Agatha Christie uses the character of Ariadne Oliver to gently satirize her own career as a writer of detective stories. A few of Christie’s personal characteristics also show up in Mrs Oliver, but Christie’s war work, marriages, travel, and daughter, have no counterparts—these show up elsewhere in Christie’s writing.
In this answer I’ll undertake a survey of the parallels between Mrs Oliver and Christie, organized alphabetically by topic. I have used spoiler markup in a few places where I discuss plot outcomes, but there might be accidental spoilers elsewhere.
Mrs Oliver goes through agonies when collaborating with Robin Upwood on a play adapted from her novels:
Robin continued blithely: “What I feel is, here’s that wonderful young man, parachuted down—”
Mrs Oliver interrupted: “He’s sixty.”
“I don’t see him like that. Thirty-five—not a day older.”
“But I’ve been writing books about him for thirty years, and he was at least thirty-five in the first one.”
“But, darling, if he’s sixty, you can’t have the tension between him and the girl—what’s her name? Ingrid. I mean, it would make him just a nasty old man!”
“It certainly would.”
Agatha Christie (1952). Mrs McGinty’s Dead, chapter 12. London: Collins.
Christie had a similar experience:
I had no idea when the idea was first suggested what terrible suffering you go through with plays, owing to the alterations made in them.
Alibi, the first play to be produced from one of my books—The Murder of Roger Ackroyd—was adapted by Michael Morton. He was a practised hand at adapting plays. I much disliked his first suggestion, which was to take about twenty years off Poirot’s age, call him Beau Poirot, and have lots of girls in love with him. I was by this time so stuck with Poirot that I realised I was going to have him with me for life, and I strongly objected to having his personality completely changed. In the end, with Gerald Du Maurier, who was producing, backing me up, we settled on removing that excellent character Caroline, the doctor’s sister, and replacing her with a young and attractive girl. As I have said, I resented the removal of Caroline a good deal; I liked the part she played in village life; and I liked the idea of village life—reflected through the life of the doctor and his masterful sister.
Agatha Christie (1977). An Autobiography, pp. 421–422. New York: Dodd, Mead and Company.
Mrs Oliver does not drink alcohol:
“I’d like to meet her. Good yarns she writes.” He lowered his voice. “But they say she drinks like a fish.”
He hurried off and Mrs Oliver said indignantly: “Really! That’s most unfair when I only like lemonade!”
Agatha Christie (1956) Dead Man’s Folly, chapter 6. New York: Dodd, Mead and Company.
Poirot looked at her rather doubtfully. Originally relieved at the mention of a party, he now again felt slightly doubtful. Since he knew that Mrs Oliver did not partake of spirituous liquor, he could not make one of the assumptions that he might have made in any other case.
Agatha Christie (1969). Hallowe’en Party, chapter 3. London: Collins.
Christie did not like alcohol either:
When I married Max [Mallowan] we enjoyed the pleasures of the table in perfect harmony, eating wisely but much too well. He was distressed to find that my appreciation of good drink—or indeed, of any drink, was nil. He set to work to educate me, trying me perserveringly with clarets, burgundies, sauternes, graves, and, more desperately, with tokay, vodka, and absinthe! In the end he acknowledged defeat. My only reaction was that some tasted worse than others! With a weary sigh, Max contemplated a life in which he should be for ever condemned to the battle of obtaining water for me in a restaurant!
Agatha Christie (1946). Come Tell Me How You Live, p. 53. New York: Pocket Books.
Mrs. Oliver was partial to apples and had indeed been known to eat as many as five pounds straight off while composing the complicated plot of The Death in the Drain Pipe, coming to herself with a start and an incipient stomach-ache […]
Agatha Christie (1936). Cards on the Table, chapter 12. London: Collins.
[At Ashfield in Torquay] There was the kitchen garden, bounded by a high wall which abutted on the road. This garden was uninteresting to me except as a provider of raspberries and green apples, both of which I ate in large quantities. […] Occasionally, after a surfeit of green apples one might have what was termed a bilious attack.
An Autobiography, pp. 9–81.
Mrs Oliver keeps gory descriptions out of her books, but some readers don’t appreciate that kind of delicacy:
“I read one of your books,” said Ann to Mrs Oliver. “The Dying Goldfish. It was quite good,” she said kindly.
“I didn’t like that one,” said Joyce. “There wasn’t enough blood in it. I like murders to have lots of blood.”
“A bit messy,” said Mrs Oliver, “don’t you think?”
“But exciting,” said Joyce.
“Not necessarily,” said Mrs Oliver.
Hallowe’en Party, chapter 1.
Christie was criticised along similar lines:
My dear James†,
You have always been one of the most faithful and kindly of my readers, and I was therefore seriously perturbed when I received from you a word of criticism.
You complained that my murders were getting too refined—anaemic, in fact! You yearned for a “good violent murder with lots of blood.” A murder where there was no doubt about its being murder!
So this is your special story—written for you. I hope it may please.
Your affectionate sister-in-law,
Agatha Christie (1939). A Holiday for Murder‡, p. vii. New York: Bantam.
† James Watts, who married Christie’s sister Madge. ‡ Better known by its British title Hercule Poirot’s Christmas.
Mrs Oliver makes a mistake over the length of a murder weapon:
Mrs Oliver cast a glance over the Penguin display. It was slightly overlaid by children’s waders.
“The Affair of the Second Goldfish,” she mused, “that’s quite a good one. The Cat it was Who Died—that’s where I made a blowpipe a foot long and it’s really six feet. Ridiculous that a blowpipe should be that size, but someone wrote from a museum to tell me so.”
Mrs McGinty’s Dead, chapter 12.
Christie had made the same mistake:
Detective Sergeant Wilson deposed to the finding of the blowpipe behind the cushion of one of the seats. There were no fingerprints on it. Experiments had been made with the dart and the blowpipe. What you might call the range of it was fairly accurate up to about ten yards.
Agatha Christie (1935). Death in the Clouds, chapter 4. New York: Dodd, Mead and Company.
(Since the blowpipe could be hidden behind an airplane seat cushion, it couldn’t be very much longer than a foot.)
Mrs Oliver is weary of her series detective, Sven Hjerson, but his popularity means that she cannot get away from him:
“I only regret one thing, making my detective a Finn. I don't really know anything about Finns and I’m always getting letters from Finland pointing out something impossible that he’s said or done. They seem to read detective stories a good deal in Finland. I suppose it’s the long winters with no daylight. In Bulgaria and Rumania they don’t seem to read at all. I’d have done better to have made him a Bulgarian.” She broke off.
Cards on the Table, chapter 8.
“I can’t help it,” said Mrs Oliver obstinately. “He’s always been a vegetarian. He takes round a little machine for grating raw carrots and turnips.”
“But, Ariadne, precious, why?” [said Robin Upwood]
“How do I know?” said Mrs Oliver crossly. “How do I know why I ever thought of the revolting man? I must have been mad! Why a Finn when I know nothing about Finland? Why a vegetarian? Why all the idiotic mannerisms he’s got? These things just happen. You try something—and people seem to like it—and then you go on—and before you know where you are, you’ve got someone like that maddening Sven Hjerson tied to you for life. And people even write and say how fond you must be of him. Fond of him? If I met that bony, gangling, vegetable-eating Finn in real life, I’d do a better murder than any I’ve ever invented.”
Mrs McGinty’s Dead, chapter 14.
Agatha Christie expressed similar sentiments about her long-running series detective, Hercule Poirot:
Hercule Poirot, my Belgian invention, was hanging round my neck, firmly attached there like the old man of the sea.† […]
It had escaped my notice that not only was I now tied to the detective story, I was also tied to two people: Hercule Poirot and his Watson, Captain Hastings. […] Now I saw what a terrible mistake I had made in starting with Hercule Poirot so old—I ought to have abandoned him after the first three or four books, and begun again with someone much younger. […]
The Hollow was a book I always thought I had ruined by the introduction of Poirot. I had got used to having Poirot in my books, and naturally he had come into this one, but he was all wrong there. He did his stuff all right, but how much better, I kept thinking, would the book have been without him. So when I came to sketch out the play, out went Poirot.
An Autobiography, pp. 263–458.
Mrs Oliver is quick to accuse doctors of being murderers:
“In that case, it’s Doctor Roberts,” said Mrs. Oliver firmly. “I felt instinctively that there was something wrong with that man as soon as I saw him. My instincts never lie.”
Cards on the Table, chapter 4.
“Last night somebody tried to push me on to the railway line at Kilchester station.” [said Poirot]
“Good gracious. To kill you, do you mean?” [said Mrs Oliver]
“I have no doubt that was the idea.”
“And Dr Rendell was out on a case, I know he was.”
“I understand—yes—that Dr Rendell was out on a case.”
“Then that settles it,” said Mrs Oliver with satisfaction.
Mrs McGinty’s Dead, chapter 13.
Christie also had a dislike of doctors, perhaps due to her experiences during her mother’s illness:
Soon after I came home from Paris, my mother had a serious illness. In the usual manner of doctors, it was diagnosed as appendicitis, paratyphoid, gallstones and few more things. […] Finally losing patience with her medical attendants, she said, “I don’t think they know—I don’t know myself. I think the great thing is to get out of the doctors’ hands.”
An Autobiography, pp. 155–156.
or to her work at the hospital in Torquay with the Voluntary Aid Detachment in the First World War:
I was given more responsibility as time went on, and I liked my work. One settled into a routine of doctors and nurses. One knew the surgeons one respected; one knew the doctors who were secretly despised by the Sisters.
An Autobiography, p. 227.
Whatever the cause, doctors and other medical practioners are murderers in many of her works:
Dr Ames in ‘The Adventure of the Egyptian Tomb’; Dr Armstrong in And Then There Were None; Norman Gale (a dentist) in Death in the Clouds; Nurse Hopkins in Sad Cypress; Dr Kennedy in Sleeping Murder; Zachariah Osborne (a pharmacist) in The Pale Horse; Dr Quimper in 4.50 From Paddington; Dr Rendell in Mrs McGinty’s Dead; Dr Roberts in Cards on the Table; Dr Sheppard in The Murder of Roger Ackroyd.
Mrs Oliver likes to wear her hair “up” despite the difficulty of keeping it in place:
The last time [Poirot] had seen Mrs Oliver, her hair style had been plain and severe. It now displayed a richness of coils and twists arranged in intricate patterns all over her head. Its prolific luxury was, he suspected, largely artificial. […]
“Wait!” implored Mrs Oliver, again with the same agony. She relaxed her grip on her head and uttered a deep sigh. Hair detached itself from its bonds and tumbled over her shoulders, a super imperial coil of hair detached itself completely and fell on the floor. Poirot picked it up and put it discreetly on the table.
Agatha Christie (1966). Third Girl, chapter 2. London: Collins.
Christie did the same:
My hair was “up,” which at that period meant done in the Grecian style, with large knots of curls high up on the back of the head and a kind of fillet round it. It was really a becoming style, particularly suited to evening dress. My hair was very long—I could sit on it easily. This for some reason was considered something to be proud of in a woman, though what it actually meant was that your hair was completely unmanageable and was always coming down. To counteract this, hairdressers created what was called a “postiche”—a large false knot of curls, with your own hair pinned away as tight to your head as possible, and the postiche pinned to that.
An Autobiography, p. 156.
Mrs Oliver was once abandoned in Harrogate:
“Naturally,” said Mrs. Oliver. “I don’t know what you think, but I haven’t the least doubt who did it. That doctor. What was his name? Roberts. That’s it! Roberts. A Welsh name! I never trust the Welsh! I had a Welsh nurse and she took me to Harrogate one day and went home, having forgotten all about me. Very unstable. But never mind about her.”
Cards on the Table, chapter 12.
Christie ran away from her husband Archie (who was having an affair) in December 1926. Her disappearance caused a sensation in the press and there was a nationwide hunt for her. She turned up eleven days later at a spa hotel in Harrogate under an assumed name. It was said at the time that she had suffered amnesia due to grief at her mother’s death, but it seems more likely that she wanted to scare or embarrass her philandering husband. Christie omitted the episode entirely from her autobiography.
Mrs Oliver has a hyperactive imagination:
“I can’t help you,” said Mrs Oliver. “I can’t imagine who could have done it. At least, of course, I can, imagine—I can imagine anything! That’s the trouble with me. I can imagine things now—this minute, I could even make them sound all right, but of course none of them would be true. I mean, she could have been murdered by someone who just likes murdering girls (but that’s too easy)—and, anyway, too much of a coincidence that somebody should be at this fête who wanted to murder a girl. And how would he know that Marlene was in the boathouse? Or she might have known some secret about somebody’s love affairs, or she may have seen someone bury a body at night, or she may have recognised somebody who was concealing his identity—or she may have known a secret about where some treasure was buried during the war. Or the man in the launch may have thrown somebody into the river and she saw it from the window of the boathouse—or she may even have got hold of some very important message in secret code and not known what it was herself.”
“Please!” The inspector held up his hand. His head was whirling.
Mrs Oliver stopped obediently. It was clear that she could have gone on in this vein for some time, although it seemed to the inspector that she had already envisaged every possibility, likely or otherwise.
Dead Man’s Folly, chapter 8.
“Of course it could be all sorts of things.” Mrs Oliver began to brighten as she set her ever prolific imagination to work. “She could have run over someone in her car and not stopped. She could have been assaulted by a man on a cliff and struggled with him and managed to push him over. She could have given someone the wrong medicine by mistake. She could have gone to one of those purple pill parties and had a fight with someone. She could have come to and found she had stabbed someone. She—”
“Assez, madame, assez!”
But Mrs Oliver was well away. “She might have been a nurse in the operating theatre and administered the wrong anaesthetic or—” she broke off, suddenly anxious for clearer details. “What did she look like?”
Third Girl, chapter 2.
“And there are plenty of other possibilities [said Poirot]. Some of them I will admit suggested by my friend, Mrs Oliver, who can easily come up with about twelve different solutions to everything, most of them not very probable but all of them faintly possible.”
Hallowe’en Party, chapter 5.
Christie was the same way:
I was, I suppose, always overburdened with imagination. That has served me well in my profession—it must, indeed, be the basis of the novelist’s craft—but it can give you some very bad sessions in other respects.
An Autobiography, p. 109.
Mrs Oliver is interested in poisons:
On the opposite side of the table Mrs. Oliver was asking Major Despard if he knew of any unheard-of, out-of-the-way poisons. […] “The people who read my books like untraceable poisons!”
Cards on the Table, chapter 2.
Christie also had an interest in unusual poisons and poisoning methods, arising from her time as a dispensing chemist in the First World War and a pharmacist in the Second.
Her use of poison was not just a convenient way to dispose of a character. Although her novels are liberally sprinkled with classic poisons such as arsenic and cyanide, Christie used a huge variety of killer compounds in her novels—too many to fit into this book. Many of the poisons she described were the drugs she was familiar with from her dispensing days.
Kathryn Harkup (2015). A is for Arsenic: The Poisons of Agatha Christie. Bloomsbury.
Christie’s stories included many types of poison:
Aconite (4.50 from Paddington); arsenic (Murder is Easy), atropine (‘The Cretan Bull’ in The Labours of Hercules); boomslang venom (Death in the Clouds); cocaine (Peril at End House); coniine (Five Little Pigs); cyanide (Sparkling Cyanide), digitoxin (Appointment with Death); eserine (Crooked House); nicotine (Three Act Tragedy); morphine (Sad Cypress); phosphorus (Dumb Witness); ricin (Partners in Crime); strychnine (The Mysterious Affair at Styles); taxine (A Pocket Full of Rye); thallium (The Pale Horse); veronal (Lord Edgware Dies).
Mrs Oliver has been known to repeat her plots:
“Women,” said Mrs. Oliver, “are capable of infinite variation. I should never commit the same type of murder twice running.”
“Don’t you ever write the same plot twice running?” asked Battle.
“The Lotus Murder," murmured Poirot. “The Clue of the Candle Wax.”
Mrs. Oliver turned on him, her eyes beaming appreciation. “That’s clever of you—that’s really very clever of you. Because of course those two are exactly the same plot, but nobody else has seen it. One is stolen papers at an informal week-end party of the Cabinet, and the other’s a murder in Borneo in a rubber planter’s bungalow.”
“But the essential point on which the story turns is the same," said Poirot. “One of your neatest tricks. The rubber planter arranges his own murder; the cabinet minister arranges the robbery of his own papers. At the last minute the third person steps in and turns deception into reality.”
Cards on the Table, chapter 8.
The reference here is to two of Christie’s works that used this device:
‘The Submarine Plans’, in which Lord Alloway, Minister of Defence, arranges for the theft of the plans for a new type of submarine, and The Murder on the Links, in which Paul Renauld intends to fake his own murder, but someone steps in and makes the murder real.
Mrs Oliver complains about readers catching her out over which flowers bloom together:
“Well, you are and you aren’t,” said Mrs. Oliver. “I am working. As you see. But that dreadful Finn of mine has got himself terribly tangled up. He did some awfully clever deduction with a dish of French beans, and now he’s just detected deadly poison in the sage and onion stuffing of the Michaelmas goose and I’ve just remembered that French beans are over by Michaelmas.”
Thrilled by this peep into the inner world of creative detective fiction Rhoda said breathlessly, “They might be tinned.”
“They might, of course,” said Mrs. Oliver, doubtfully. "But it would rather spoil the point. I’m always getting tangled up in horticulture and things like that. People write to me and say I’ve got the wrong flowers all out together. As though it mattered.”
Cards on the Table, chapter 17.
This seems as if it ought to be a reference to a specific mistake of Christie’s, but I have been unable to identify it.
This article suggests that Oliver was an exaggeration of herself. I expect she had fun doing that!
Ariadne Oliver is a successful detective novelist that appears in two short stories (with Parker Pyne in Parker Pyne Investigates) and seven novels (six of them with Hercule Poirot). The middle-aged writer of detective stories is broad-shouldered and has "rebellious" gray hair, sometimes accentuated with hair extensions. Ariadne Oliver is known for her love for apples and her strong belief in woman's intuition. She is also the creator of the Finnish detective Sven Hjerson, of whom she has a great dislike. The character of Mrs. Oliver is an exaggerated version of Agatha Christie herself (Agatha has shown dislike towards Poirot, her creation, and Agatha was known for eating apples, too).
That doesn't answer your question to what extent the character actually resembles Christie, but it does vindicate your theory. It could be interesting to assess a biography of Christie against the character. (It may well have been done already, but I haven't found it. Yet.)