Question: What is previous work lacking？
Evidence: Many social and psychological studies have worked towards a definition of cyberbullying. A common starting point for conceptualising cyberbullying are definitions of traditional (or offline) bullying. Seminal work has been published by BIBREF23 , BIBREF24 , BIBREF25 , BIBREF26 , who describe bullying based on three main criteria, including i) intention (i.e., a bully intends to inflict harm on the victim), ii) repetition (i.e., bullying acts take place repeatedly over time) and iii) a power imbalance between the bully and the victim (i.e., a more powerful bully attacks a less powerful victim). With respect to cyberbullying, a number of definitions are based on the above-mentioned criteria. A popular definition is that of BIBREF21 which describes cyberbullying as “an aggressive, intentional act carried out by a group or individual, using electronic forms of contact, repeatedly and over time, against a victim who cannot easily defend him or herself”.
Nevertheless, some studies have underlined the differences between offline and online bullying, and have therefore questioned the relevance of the three criteria to the latter. Besides theoretical objections, a number of practical limitations have been observed. Firstly, while BIBREF23 claims intention to be inherent to traditional bullying, this is much harder to ascertain in an online environment. Online conversations lack the signals of a face-to-face interaction like intonation, facial expressions and gestures, which makes them more ambiguous than real-life conversations. The receiver may therefore get the wrong impression that they are being offended or ridiculed BIBREF19 . Another criterion for bullying that might not hold in online situations, is the power imbalance between bully and victim. Although this can be evident in real life (e.g. the bully is larger, stronger, older than the victim), it is hard to conceptualise or measure in an online environment. It may be related to technological skills, anonymity or the inability of the victim to get away from the bullying BIBREF27 , BIBREF17 , BIBREF28 . Empowering for the bully are also inherent characteristics of the Web: once defamatory or confidential information about a person is made public through the Internet, it is hard, if not impossible, to remove.
Finally, while arguing that repetition is a criterion to distinguish cyberbullying from single acts of aggression, BIBREF23 himself states that such a single aggressive action can be considered bullying under certain circumstances, although it is not entirely clear what these circumstances involve. Accordingly, BIBREF27 claim that repetition in cyberbullying is problematic to operationalise, as it is unclear what the consequences are of a single derogatory message on a public page. A single act of aggression or humiliation may result in continued distress and humiliation for the victim if it is shared or liked by multiple perpetrators or read by a large audience. BIBREF29 compare this with a `snowball effect': one post may be repeated or distributed by other people so that it becomes out of the control of the initial bully and has larger effects than was originally intended.
Given these arguments, a number of less `strict' definitions of cyberbullying were postulated by among others BIBREF6 , BIBREF5 , BIBREF1 , where a power imbalance and repetition are not deemed necessary conditions for cyberbullying.
The above paragraphs demonstrate that defining cyberbullying is far from trivial, and varying prevalence rates (cf. Section SECREF1 ) confirm that a univocal definition of the phenomenon is still lacking in the literature BIBREF1 . Based on existing conceptualisations, we define cyberbullying as content that is published online by an individual and that is aggressive or hurtful against a victim. Based on this definition, an annotation scheme was developed (see BIBREF30 ) to signal textual characteristics of cyberbullying, including posts from bullies, as well as reactions by victims and bystanders.
Nevertheless, some studies have underlined the differences between offline and online bullying, and have therefore questioned the relevance of the three criteria to the latter.
Answer: They lack a clear definition of cyberbullying.