Rewriting characters: The Big Bang Theory

Penny meets Sheldon and Leonard in Rewriting Characters: The Big Bang Theory.

As part of my scriptwriting aspirations, I was interested to understand how a hugely successful TV show knows right from the start what people will watch whilst making content unique. This led me to read drafts and pilot episode scripts of TV shows and I soon realised that those making these shows often don’t get everything spot on at the start. In particular, this article focuses on rewriting characters in the phenomenally successful, long-running TV sitcom The Big Bang Theory.

I have seen from a few pilot scripts how some successful TV shows contained ideas in early drafts that didn’t make it to the screen because characters or situations were not likeable, believable, intriguing or funny enough. So there’s a job change here, a character tweak there, an event reordered — even a simple name change can make a difference.

With characters and situations redefined, dropped, or introduced, we then watch the show on screen as if the writers had always intended it that way.

I wondered whether the most important element of the script really is the character. So here I set out my analysis of some of the changes that were made to characters in the pilot drafting process of the The Big Bang Theory for it to be picked up by a network. And it’s a fitting time to write about this show, with its final ever episode airing on 16 May 2019.

All images from the show appearing in this article are credited to Warner Bros/CBS. Please read the Fair Use notice at the end of this article.

The Big Bang Theory

My discussion focuses on the following:

  • original unaired pilot (Jan 2006) (about)
  • revised pilot draft script (Oct 2006) (here)
  • revised aired pilot (Sep 2007)
  • seasons 1—6 (2007—2012) and 12 (2019)

For those not aware, the revised pilot is the aired version where the main female character had been replaced. In the revised (aired) pilot, the main female character is Penny (played by Kaley Cuoco). In the original (unaired) pilot, the main female character is Katie (played by Amanda Walsh).

Katie becomes Penny

That both the aforementioned pilot shows exist is a case in point for character changes making a TV series a success. Katie had proved to be unpopular with test audiences who thought she was abrasive and overly mean and sarcastic to Leonard and Sheldon.

If you have watched The Big Bang Theory (which I presume you have if you are reading this) then you might think, well, Penny is sometimes like that, isn’t she? But she is only like that when provoked — in the early days she is provoked by Leonard, Sheldon, Howard and Raj, expanding in later seasons to include Amy and Bernadette. On the whole, she is a pleasant and likeable character and we mostly support her reaction to the often decidedly odd behaviour of the four nerdy guys.

In the first draft script for the revised pilot we do meet a more edgy Penny though. It’s as if the writers had her penned somewhere between crass Katie in the original pilot and perky Penny in the aired series.

In the revised pilot script and episode, Leonard and Sheldon first see Penny when she has just moved into the apartment across the hall, having split up from her boyfriend Kurt. She is happily unpacking the boxes just before she sees the two guys through the doorway (below left). But in the draft script she is “dancing with reckless abandon” as she sets light to a photograph of Kurt. Now those there are two very different Pennies.

Then there is the original pilot which sees Leonard and Sheldon first meet Katie when she is bickering on the phone as she sits on the edge of the pavement with her luggage beside her (below right).

Meeting Penny (L) and Katie (R) (credit: Warner Bros/CBS)

I probably wouldn’t have tuned in again after seeing the original pilot with the Katie character as the female lead. She is surly, sullen, sulky and gruff throughout the whole episode. I would also add here that I only liked the early years of the aired show, when the focus was on the four nerdy guys and their interaction with Penny, with just a few regulars and guests.

Swapping Katie for Penny also changed the dynamic because the antagonistic element was originally assigned to Katie. In the aired show, the antagonist is Sheldon Cooper.

Now here’s something to consider: would the show have lasted anywhere near as long if Sheldon Cooper had not been the Sheldon Cooper we know? Probably not. And that has as much to do with the Jim Parsons interpretation of the character as it does his lines in the script.

But as the cast expanded, I contracted. And as the nerdy writing got diluted and the cast became more diverse, I switched off from regular viewing, which was just after Season 4 (2010-2011).

I did catch up gradually to Season 6 over time and then watched nothing regularly thereafter other than catching the odd episode, and those I did watch often felt lacklustre in comparison to earlier years.

However, whilst writing this article I thought I’d better get up-to-date, so I have just watched the entire final season (S12) on Amazon Prime, as well as some of the other seasons I missed, or at least those I could summon up the will to watch.

Friends with physics

As an aside, in 2007 and just two months before the pilot show aired on 24 September, I had just graduated with a degree in physics myself and I enjoyed spotting the traits of all the people I had met on the course in the early characters in the show.

But much earlier, just after I had started the degree, in 2003, I recall being at a friend’s wedding and saying to the bride’s brother-in-law sitting next to me that I thought my experience so far of the people in my class would make for an entertaining sitcom about nerds on a physics course, like Friends with physics, I said.

That’s an absolutely true story but purely coincidental.

But in my version, the main nerd was a woman, based on a true character of course, much like the Sheldon character, which is after all just a stereotype. In 2007, when The Big Bang Theory came out, I told her about my earlier idea and about her character. I remember we were at a barbeque hosted by another of our weird physics cohort; when I told her, she emphatically refused to accept being anything like Sheldon and told me that I was more like Sheldon than she was and it turned into a ridiculous debate as to why. She couldn’t be ‘more wrong’ of course, because she’s almost a carbon-copy. I thought it was a compliment but she didn’t see it that way.

My most interesting character was one much like Raj as far as wardrobe went, another stereotype and also based on someone in our cohort, although he disappeared from class at the end of the first year and no-one ever heard from him again. There was one particular flirty female character (but not like Penny) who always seemed to have her eye on some new conquest in the class. I was going to be the one who didn’t seem to belong there and whose intelligence was always called into question.

I’ve always wondered: is it better to look more intelligent than you are, or be more intelligent than you look?

Anyway, enough of that, it’s passed now.

I must add here that Sheldon’s character is so iconic that two Taiwanese astronomers chose to name one of the asteroids they discovered after him — asteroid 246247 Sheldoncooper (2007 SP14).

If you’ve looked at any other parts of my website, you will not be surprised that I managed to slip mention of an asteroid into this post — and indulge me for while here, because it wouldn’t be right not to go off on a nerdy tangential trajectory at some point in this article. So here we go.

Asteroid 246247 Sheldoncooper (2007 SP14)

Asteroid 246247 Sheldoncooper is located in the main asteroid belt and orbits at around 2.8 AU between Mars and Jupiter, roughly at the distance where you would find dwarf planet 1 Ceres. I’ve only mentioned Ceres to give you an idea of where Sheldoncooper resides in the Solar System, because Sheldoncooper could be up to three orders of magnitude smaller than Ceres.

At 2.8 AU, Sheldoncooper is not orbiting close to Earth like the asteroids 101955 Bennu, 162173 Ryugu and 25143 Itokawa. No doubt you have read about those three asteroids in the news; they are near-Earth asteroids orbiting at a distance of 1.1 AU, 1.2 AU and 1.3 AU, respectively (although no doubt they originated in the main belt, like Sheldoncooper). I’ll just clarify here that 1 AU (astronomical unit) is the Earth-Sun distance, about 150 million km.

I used the formula provided in the NASA-JPL Asteroid Size Estimator to estimate the diameter of asteroid Sheldoncooper using its absolute magnitude and albedo. The absolute magnitude is 15.8 according to the NASA-JPL Small-Body Database. But there is no information about its albedo (related to how much sunlight it reflects), so I used the whole albedo range allowed by the estimator (0.05–0.30). The calculation gives Sheldoncooper’s average diameter somewhere in the region of 2–4 km. That’s an average diameter assuming the body is spherical.

However, most asteroids are irregularly shaped and more like lumpy potatoes — and some have even more scrappy shapes like dumbbells, as you can see in this graphic that I produced showing all the asteroids that have been visited by spacecraft.

It’s only when an asteroid’s average diameter gets to around 400–600 km — or a radius of 200–300 km, known as the potato radius — that it transitions from irregular to spherical, like the almost spherical 4 Vesta and 1 Ceres which have diameters of 525 km and 945 km, respectively. This is because at that size (400–600 km diameter), the asteroid will have enough self-gravity to overcome rigid body forces to pull itself into a more rounded shape to achieve hydrostatic equilibrium.

You can read about the potato radius here and here, or on Wikipedia under the section relating to hydrostatic equilibrium and dwarf planets. Actually, the potato radius is one of my favourite subjects, along with the brazil nut effect and its application to asteroids (you can read about that here).

At which end of the 2–4 km size range asteroid Sheldoncooper falls depends on its albedo, which depends on its spectral type, which I’m not aware has been determined yet. But if it is a C-type or carbonaceous asteroid (like Ryugu, Bennu and Ceres), it will have a low albedo and be at the larger size estimate. Whereas if it is an S-type or similarly silicate-rich stony asteroid (like Vesta and Itokawa), it will have a higher albedo and be at the smaller size estimate.

Asteroid 246247 Sheldoncooper was discovered by Quan-Zhi Ye and Hung-Chin Lin at Lulin Observatory in Taiwan on 20 September 2007. Its initial designation of 2007 SP14 reflects that date. Interestingly, that date was four days before the revised pilot episode of The Big Bang Theory (with Penny) aired in the US.

Here is an orbit diagram of the position of the asteroid on the day the pilot episode aired, on 24 September 2007:

Orbit diagram of asteroid 246247 Sheldoncooper (2007 SP14).

Orbit of asteroid 246247 Sheldoncooper
(credit: NASA-JPL Small-Body Database)

So, minor detour to the asteroid belt over, now back to rewriting characters in The Big Bang Theory.

Sheldon and Leonard

In both the aired and unaired pilot episodes, Sheldon Cooper is markedly less asexual than his character becomes as the series continues. He even flirts with both the Katie and Penny characters on first meeting and swoons as he claims ownership of his equation-covered whiteboard — and not because of the math.

In the unaired pilot, Sheldon lets someone touch his food without complaining, drinks alcohol and talks about women’s butts. He also talks about having had sex. Even in the draft script for the aired pilot, Sheldon talks about an upcoming fantasy and science fiction convention as being “a great place to meet women”.

Sheldon’s character in the pilots (L: unaired, R: aired) (credit: Warner Bros/CBS)

These traits are all at odds with the Sheldon we know. In fact, Leonard in the unaired pilot is more like Sheldon than Sheldon is. It is clear that these roles were switched by the time the revised pilot hit the screens. Sheldon’s distinctive character then takes next to no time to develop into the one we know, taking shape during the first few episodes of Season 1.

So although Leonard was intended to be the lead character in the show (you only have to look at the opening title sequence to see Johnny Galecki’s name appear first), only a few episodes into Season 1 and it already seems odd that that Parsons didn’t have top billing.


The character of Gilda (below, left), Leonard’s girlfriend in the unaired pilot seems to be a prototype of the character introduced in Season 3 as Sheldon’s frumpy girlfriend, Amy (below, in the red waistcoat).

Gilda is an engaging character (as are all the nerdy girls in the show) albeit short-lived for one episode only. In fact, some of her lines are recycled for Amy later on. Some people have, however, likened Gilda to Leonard’s girlfriend, Leslie Winkle (below, in the green hoodie) and I suppose Gilda may be a hybrid of Leslie and Amy.

However, it is clear that Amy’s character essentially replaces Leslie’s character in terms of the token female nerd in the show — the switch is in the last episode of Season 3, as Leslie slams her apartment door in Leonard’s face and we see her for the last time, Sheldon opens the door to the coffee shop and meets Amy for the first time, having been set up on a blind date by his friends via an online dating site.

There is a guest appearance by Leslie years later in Season 9, but that’s irrelevant to this discussion.

Early female characters (L-R: Gilda, Leslie, Amy, Penny) (credit: Warner Bros/CBS)

At the end of the aired pilot, we see Leonard declare his love-at-first-sight for Penny to Sheldon with the prediction “our babies will be smart and beautiful”. As the show moves on, Penny evolves from the sweet and smiling girl-next-door and she and Leonard have an on-off relationship throughout the entire series. She is loathed by Leslie who describes her as “middle-Earth Barbie” in the excellent episode The Barbarian Sublimation (S2, Ep 3), which sees Penny’s brief demise into the addictive world of online gaming, by which time Penny has become a more disparaging character. However, Penny is looked up to by Amy, who admires her blend of feisty allure — and sometimes a little too much.

I rather liked Leslie’s character and on the whole I didn’t mind Amy’s character joining the main cast, but the latter is to a large extent because it was Mayim Bialik. Although I never saw Blossom, I remember her playing Bette Midler’s young C.C. Bloom in Beaches and she is a truly superb talent (clearly with a first class brain too).

I never took to the Bernadette character and this was not an insignificant factor in me disengaging with the sitcom after Season 4. By the end of Season 6, I had watched enough with Bernadette’s character annoying the hell out of me. I could just about cope with Leonard’s excessive whining but not the pitch of Bernadette’s voice too.

Koothrappali and Wolowitz

Neither Howard Wolowitz nor Rajesh Koothrappali appear in the unaired pilot, but they both appear in the revised pilot script and, as we know, in the aired pilot. However they don’t both translate equally from the script to what we see on screen.

In the revised pilot script, the Wolowitz character is much like what we see on screen. However, without Simon Helberg’s well-judged timing and spot-on delivery, the lines written for this character could still have failed dismally to entertain on screen.

In the draft revised pilot script, Koothrappali is described as being a particle physicist and is an American of Indian parentage and named Dave. In the aired show, Koothrappali is Indian not American, described as being an astrophysicist and is named Rajesh, generally known as Raj.

However, from what I saw in the first three seasons, Raj (played by Kunal Nayyar) spent his time investigating the size distribution of Kuiper Belt Objects and discovered a new trans-Neptunian Object, which is more planetary astronomer than astrophysicist. Only later in the aired show did this character’s research start to resemble something a particle physicist might be involved with when, in Season 3, he interviewed (unsuccessfully) for a research position in stellar evolution, before going on to work with Sheldon Cooper on string theory, in particular studying gamma rays from dark matter annihilations and its implications on string theory.

As soon as Dave Koothrappali is introduced in the draft revised pilot script, we are made aware that he is obsessively concerned with the implications of microwaves on his body and we are told his baseball cap and trousers are lined with kitchen foil to reflect the radiation. This was not written into Raj’s on-screen character — indeed it would have been completely out of character for Raj to get hung up on such health issues, because despite his regular pilates practise, his diet is not short of alcohol, chocolate, lattes and Chantilly cream, and he is seen to let his pet pouch Cinnamon lick his face.

Try and imagine watching the show in one or other of the alternate forms — Katie rather than Penny, a less antagonistic Sheldon, a Sheldon-like Leonard with an Amy-like girlfriend, a Dave rather than Raj, and a Howard just as he is. Would it still be a hit?

Well, it was rewritten because the script wouldn’t sell with most of the characters the way they were. So the answer is clearly no — indeed Sheldon might say the question is moot: the script wouldn’t sell, ergo it wouldn’t get the chance to be a hit.

The expanding main cast (credit: Warner Bros/CBS)

So in a sitcom, is it the characters that make or break a script more than the story? Discuss. And what do you do when you have a character you instilled with a certain trait, then a few seasons into the show you don’t want to write about it anymore?

Writing out a character trait

One trait that did survive the rewrites is that the draft Dave and actual Raj Koothrappali characters suffer from selective mutism, which manifests itself in him being unable to speak in front of women (although this doesn’t apply to relatives, as we see him converse freely with his sister Priya and his mother).

The selective mutism is prominent at the start of the show’s long run, but the affliction is gradually played down using various fixes during subsequent seasons. By Season 4, I got the impression that the writers were hoping that the audience would forget about the problem, so that they could have Raj interact with the rest of the characters with normal dialogue.

So Raj’s affliction is ultimately seen off half way through the show’s run (S6, Ep 24) in a rather woolly way, in my opinion. It reappears briefly in the final season (S12, Ep 8) during Raj’s first overnight stay with his newly acquired fiancé Anu, but that is swiftly dealt with by Raj consuming half a bottle of wine.

Personally, I thought that Simon Helberg’s Wolowitz character delivering Koothrappali’s lines was up there with some of the most entertaining moments in the entire show. Also, Kunal Nayyar’s ability to portray Raj’s intention with just facial expressions and hand movements showed terrific talent. Overall, I am torn between whether the Helberg-Nayyar double act is a case of artificial or natural selection.

Dealing with Raj’s selective mutism (credit: Warner Bros/CBS)

When the writer’s had had enough of writing around Raj’s selective mutism, they made a series of attempts at wriggling out of having written it in, in what seems to be just one thread of evolution in rewriting characters for the The Big Bang Theory:

#1 — Voiced-over thoughts. Season 1 (Ep 2): For one scene only, when Penny and Raj pass in the hallway, the writers tried having Raj’s thoughts voiced over by him. I wonder whether the plan had been to do this in future episodes. The thing is, it didn’t really work and so it wasn’t used again.

#2 — Drinking alcohol. Season 1 (Ep 8): Raj’s affliction is found to go away when he drinks alcohol, sometimes to the point of losing all his inhibitions with embarrassing effects — recall when he was fixed up with Lalita Gupta and tells her how fat she used to be, and when he tries to chat up a girl in a coffee shop and strips naked. Alcohol is then used repeatedly throughout the first six seasons so that the writers didn’t have to rely on Wolowitz delivering the lines. Although it did require the writers to plan Raj’s daytime alcohol-free interactions very carefully so as not to have him still whispering into ears. The writers solved the daytime issue for a while by having Raj carry a hip flask.

#3 — Drug trial. Season 1 (Ep 15): The drugs didn’t work though, producing hand tremors and wearing off at inopportune moments. A variation of this could have been used to nip the selective mutism trait in the bud before the humour surrounding it became stale, but it wasn’t.

#4 — Placebo effect. Season 2 (Ep 7): During a train journey, the guys discover that alcohol-free beer works just as well as the real thing, so long as Raj doesn’t realise it’s alcohol-free. I believe this was used only once.

#5 — Heartbreak. Season 6 (Ep 24): Breaking up from his girlfriend Lucy cures Raj’s selective mutism. Now the writers didn’t have to deal with it again. Until the final season (S12, Ep 8) that is, when Raj has a relapse and the alcohol solution has to be re-invoked.

Guest characters

By the time we get to Season 6, I think the show generally loses its edge, in part due to using an expanded main cast rather than just bringing in interesting one-off guest stars to liven up the episodes, and in part because the stories were not as imaginative.

Is there anything to this, or did I just get bored? Take a quick look at the Wikipedia page that lists all of The Big Bang Theory episodes and the respective writers, ratings and rankings, and note what jumps out at you. One day I will do a statistical analysis of that data, unless someone has already done it, in which case I look forward to your comments below.

In the meanwhile, The Loobenfeld Decay (S1 Ep 10) with DJ Qualls guest starring as Sheldon’s fake drug-addled cousin Leopold, is my number one for its brilliantly constructed — and OK, let’s just say it, exquisitely convoluted — story. It also has a splendidly provocative and censored vanity card (#198c) which explains a particular change that Chuck Lorre had to make to the script when referring to the title of one unseen character in order for the network to agree to air it.

Below is a brief synopsis of the episode — and it’s not an entirely unrelated detour away from my theme of character analyses, because the episode itself is about a character concocted by Sheldon and includes what, to the person playing the character, works and doesn’t work about his story and the lines in the script he has been given by Sheldon. Hopefully you’ll see what I mean.

But let’s just start with Sheldon’s tee-shirt in one scene in the episode — for me it sums up the way the whole episode is heading. I presume it was an intentional placement. The tee-shirt depicts a sort of fractal that illustrates the excruciating and finely detailed structure that Sheldon has woven into a lie he has constructed that never seems to end, as well as the steady decline of Sheldon’s fake-cousin Leopold’s character into drug addiction, and if that wasn’t enough, the collapse of Sheldon’s character synopsis for Leopold that his work colleague, Toby Loobenfeld, has agreed to play but who refuses to stick to the script.

The fake Leopold character has been constructed by Sheldon to cover up a lie constructed by Leonard which dupes Penny into believing they have a symposium to go to, to avoid having to go and hear her sing in a one night showcase of Rent. Thinking that Penny will see through Leonard’s symposium lie, Sheldon concocts a drug intervention lie, making Penny believe that Leonard’s lie was to cover up Sheldon’s shameful family tie. The rest of the episode follows a path of gradual implosion, as depicted by Sheldon’s tee-shirt.

It’s a must see.

The Loobenfeld Decay (S1, Ep 10) (credit: Warner Bros/CBS)

My second favourite episode is The Barbarian Sublimation (S2, Ep 3), which, as I referred to above, depicts Penny’s brief demise into an online gaming addiction, an episode written by Chuck Lorre’s daughter, Nicole Lorre (who is involved on the show’s production). It has, in my opinion, a lot of similarities in its set-up to The Loobenfeld Decay that bind into another clever episode. Both episodes use the themes of addiction, assuming alter-egos, in-story character analyses, and interventions. Some very useful techniques to consider when writing characters for a one episode script, maybe.

The finale

Season 12 will be the last for this show, with the big finale airing on 16 May 2019 in two back-to-back episodes (23 and 24). Media reports say that the show was wound up because Jim Parsons wanted to move on. In an interview with Entertainment Weekly on 3 January 2019, he says “…it feels like we’ve chewed all the meat off this bone.”

Despite my waning interest in watching the later years of the show, I am glad I took the time to watch Season 12 and some of the second half of the series, although my thoughts haven’t changed about how lacklustre it is compared to the early years.

Unlike the very early enjoyable episodes, the final season is lazy due to the stories continuing over two and sometimes three episodes; the long drawn-out storylines become boring compared to the quick and clever standalone twenty minute stories. I don’t think I laughed once in the flat pre-penultimate episode (22).

The writers definitely tried to go full circle in the final season, with reminders of past themes popping up as the end of the series approached, such as Raj’s brief bout of selective mutism, Howard’s brief ownership of a moped, and a variation of when Sheldon met Leonard. Events were also turned on their heads with Amy behaving like Sheldon, Sheldon letting things slide, and Kripke briefly being nice to Sheldon.

My predictions: An inevitable Nobel Prize for Sheldon (and Amy) and some kind of big event for Leonard (and Penny).

My preference: A Big Crunch, with everything subsequent to the pilot episode having been Leonard’s “Bobby coming out of the shower” dream scene and the original five cast members ending up back on the couch as they were at the start of 2007. Better still, show the guys returning to their pasts after their excursions to visit their futures in the time machine they purchased on eBay in Season 1 (Ep 14), ending up back at Leonard and Sheldon’s apartment with Penny moving in next door.

And the post-mortem: Of course it ends with the inevitable Nobel Prize, at an award ceremony with Sheldon ditching the very long speech he had prepared about himself in favour of crediting his success to the group of friends he loves who are all in the audience with…Buffy The Vampire Slayer. In a Big Hark back to the pilot episode, Sheldon repeats Leonard’s prediction made the day he met Penny, as he tells the world of their happy event: that their babies will be smart and beautiful.

So that’s it for Rewriting Characters: The Big Bang Theory. If you enjoyed this, take a look at my follow-on article Rewriting characters: Goliath Season 1, or my article on Season 6 of the Amazon police drama Bosch, Bosch Asks: What’s a Medical Physicist?

As an aside, some time ago I had an idea that I would write a spin-off pilot script around one particular character in The Big Bang Theory (not Sheldon) and send it off to someone in the know for comments. Of course, sending off speculative submissions is not always a good idea — take the incidents surrounding the idea for the 1951 Billy Wilder film Ace In The Hole, for instance — but that’s a whole different post for a whole new day.

Fair Use Notice. All images from The Big Bang Theory shown in this article are credited to Warner Bros/CBS. I am using the imagery to illustrate my discussion about characters and scriptwriting. All images used have been carefully selected to support the critical commentary in this article, such as identifying key moments and key episodes visually. I believe this constitutes a ‘fair use’ of any such copyrighted material.