Table 2.

A non-exhaustive taxonomy of common adversarial tactics

Misrepresentation of scientific evidence/expertise
Straw-manning	Misrepresenting scientific arguments to make them amenable to ridicule or attack, and to deflect or obscure evidence that undermines a particular narrative.	‘Mercury is toxic, yet scientists put it in vaccines!’—This statement belies importance of dose and ignores the fact there is no evidence for harm from thimerosal in vaccines.
Cherry-picking/quote mining	Selective, manipulative filtering of scientific evidence or expert statements, taken out of context to undermine evidence base or promote a narrative.	‘THC kills cancer, but doctors don’t want you to know about cannabis cures.’—THC can kill cells in a Petri dish, but killing plated cells is entirely different from treating human cancer.
Shifting the burden of proof	Insisting the onus is on scientists to ‘disprove’ claims rather than offering any evidence or rationale for assertions made.	‘GMOs are toxic, and scientists should prove us wrong.’—This assertion is untrue, and onus lies on those making the claim to proffer evidence for it.
Discreditation attempts
Questioning qualification	Casting doubt on one’s ability to question claims at hand. Typically, ostensible scepticism is not extended to claims supportive of the narrative.	‘This patient advocate isn’t an expert, so they can’t say this vaccine is safe!’—One does not need to be an expert immunologist in this case to accurately reflect medical consensus.
Alleging vested interests	Claims that the speaker is compromised due to some apparent conflict of interest or that experts are otherwise lacking impartiality.	‘Who’s paying you to say this?’—Unsubstantiated allegation to deflect from absence of evidence for a narrative or claim.
Asserting conspiracy theory	Allegations that the scientist, physician or patient advocate is part of some conspiracy to suppress the truth or spread false information, either as a pawn or an active player.	‘She’s part of a pharma cover-up to suppress natural cancer cures!’—Appeals to conspiracy theory function to distract from lack of evidence.
Dubious amplification of pseudoscientific narratives
Media targeting	Targeting traditional or online media outlets to amplify dubious narratives, typically bypassing gatekeepers (science/health journalists, and so on) who would otherwise be more likely to spot pseudoscience.	Pitching dubious health claims to journalists as human interest stories—This approach was successfully used by antivaccine activists to push the discredited link between autism and the MMR vaccine between 1998 and 2000.
Astroturfing/sockpuppeting	Use of fake social media accounts/fictitious pressure groups to provide an illusion of a wider grassroots support for a particular narrative.	Example: Accounts which spring up once an initial antifact site is blocked but which include misinformation consistent with the originator’s initial social media accounts.
Celebrity endorsement	Celebrities and influencers can have disproportionately large impact on the perception of public even in areas where they have no relevant expertise or knowledge.	There are numerous examples of this, especially in relation to antivaccine activism, including actors and models being cited for their purported knowledge of complex health issues.
Malicious complaints/abuse of regulatory frameworks
Poisoning the well/smear campaigns	The spreading of malicious claims regarding an individual’s professional or personal conduct to undermine them or discourage others from engaging with them.	‘I’ve heard that doctor abuses patients.’—Inflammatory slurs such as these are designed to discredit, and are not in any way substantiated, but calculated to invoke disgust or contempt.
Vexatious complaints to employers	Making calculated complaints to one’s employer or threatening to do so in order to intimidate them into silence.	Exaggerated/misleading accounts of interactions with public advocates and demands to censure them, typically aimed at an individual’s university or employer.
Vexatious complaints to regulatory bodies	Abusing procedures of professional bodies to target a researcher/medic who presents a challenge to a narrative. These may also include unwarranted freedom of information requests or vexatious parliamentary questions.	Registering complaints with a medical regulatory body against a doctor for their advocacy of evidence-based positions. Physicians especially vulnerable, as typically all complaints must be investigated, regardless of merit.
Intimidation
Harassment/abuse	Harassment can take many forms, and personal abuse is perhaps most common. Threats (implied and direct) are often employed.	Abusive language made publicly or in direct messages, and posting of private contact details, phone numbers, addresses, and so on.
Legal threats	Legal notices and mechanisms can also be used to silence researchers questioning a narrative, from cease and desist notices to defamation claims.	Threatening to bring an advocate to court for alleged defamation, also used judiciously to limit independent investigation on pseudoscientific narratives.
Physical intimidation	Implicit or explicit threats of physical violence are an unfortunately potent method of intimidating scientists into silence. This includes threats of physical violence or rape (the latter usually directed at female discussants).	Stalking of private abodes, explicit threats, or actions like spitting, and so on. There are instances of security being required for scientific meetings on publicly contentious subjects, due to implications of or threats of violence.

GMO, genetically modified organism; MMR, measles, mumps and rubella; THC, tetrahydrocannabinol.