1 Journal of Homeland Security and Emergency Management Volume 8, Issue Article 41 Active Shooter on Campus: Evaluating Text and Warning Message Effectiveness David N. Sattler, Western Washington University Katy Larpenteur, Western Washington University Gayle Shipley, Western Washington University Recommended Citation: Sattler, David N.; Larpenteur, Katy; and Shipley, Gayle (2011) "Active Shooter on Campus: Evaluating Text and Warning Message Effectiveness," Journal of Homeland Security and Emergency Management: Vol. 8: Iss. 1, Article 41. DOI: / Available at: Berkeley Electronic Press. All rights reserved.
2 Active Shooter on Campus: Evaluating Text and Warning Message Effectiveness David N. Sattler, Katy Larpenteur, and Gayle Shipley Abstract Recent events involving active shooters on campus underscore the importance of promptly notifying the campus community so students, faculty, and staff can take protective action as the incident develops. This study (a) developed warning messages informing the campus of an active shooter that can be delivered to cellular telephones and accounts, and (b) assessed their effectiveness. Participants were 264 (76 men, 188 women) undergraduate students at Western Washington University who indicated their understanding of and anticipated responses to text and messages. Participants indicated that they understood the instructions and would take the actions indicated in the messages. The results indicate text and messages are effective ways to notify and provide coherent instructions to the community during a life threatening emergency. This approach may be modified to create templates for other emergencies and disasters (e.g., earthquakes, tornadoes). KEYWORDS: active shooter, warning message, emergency warning, emergency preparedness, message template, text messages, messages Author Notes: The warning messages were written by David N. Sattler, Gayle Shipley, Paul Cocke, and the Western Washington University Emergency Management Committee. We thank the editor, three anonymous reviewers, and Virginia Shabatay for their helpful comments. Address correspondence to David N. Sattler, Department of Psychology, Western Institute for Social Research, Western Washington University, Bellingham, Washington ;
3 Sattler et al.: Evaluating Text and Warning Messages 1 United States federal law requires higher education institutions to immediately notify the campus community upon the confirmation of a significant emergency or dangerous situation involving an immediate threat to the health or safety of students or staff occurring on the campus (Jeanne Clery Disclosure of Campus Security Policy and Campus Crime Statistics Act, Public Law ; U.S. Department of Education, 2008). Recent events across the country (e.g., active shooter at Virginia Polytechnic Institute and State University; University of Alabama) underscore the importance of promptly notifying students, faculty, and staff so they can take protective action as an incident develops. Between 2005 and 2007, there were 12,181 aggravated assaults and 104 murders on public and private 4-year college campuses (U.S. Department of Education, 2008). Higher education institutions are taking new measures to notify the campus community about an emergency situation, including the use of text messages sent to cellular telephones and messages. However, few projects have assessed the effectiveness of these messages or their ability to accurately convey information about an event. This is especially important in the case of text messages sent to cell phones because they are limited in length and typically have an upper limit of 160 characters and spaces per message (Plummer & Johnson, 2008). Can vital information be conveyed in 160 characters or less? Can receivers comprehend abbreviated information contained in a text message? Will recipients trust the source of the and text messages? This project assesses the effectiveness of text messages and messages that were developed to be issued in the case of an active shooter on a university campus. Cell phone text messaging and have several benefits when compared to more traditional media (e.g., television, radio). Most students own a cell phone, carry the phone with them on campus, and use and the internet (Junco & Cole-Avent, 2008). While on campus, students likely have greater access to a cell phone or than to television or radio. Furthermore, text and messages are issued and delivered by the original source of information (viz., the institution s communications office; Lindell & Perry, 2004). However, text messaging and also have limitations. Cell phones and the internet may be more vulnerable to service disruption than television or radio. There are concerns as to whether all necessary information can be included in a text message that is limited to 160 characters and spaces. Effective warning messages must (a) describe the situation clearly so that people understand the danger, (b) be issued by a credible source, (c) include specific information indicating the location and time of the event, and (d) state Published by Berkeley Electronic Press, 2011
4 2 JHSEM: Vol. 8 , No. 1, Article 41 protective actions (Mileti & O Brien, 1992; Mileti & Peek, 2000). The message must include sufficient details about the situation in order for the recipient to perceive a threat, and have trust and confidence in the message source, content, and recommendations. If more than one message is issued, subsequent messages must be consistent with prior messages in order to avoid contradictory and confusing information. The characteristics of individuals who receive the message (e.g., gender, age, self-efficacy, disaster experience, locus of control) influence the likelihood whether they will perceive the situation as an emergency and take protective action (Mileti & Peek, 2000; Riad, Norris, & Ruback, 1999; Sjoberg, 2000). For example, someone low in self-efficacy may be less confident in his or her ability to take preventive actions (Lindell & Perry, 2004). Individuals with an internal locus of control (the belief that the individual can control what happens to him or her) tend to take more preventive actions in disasters than those with an external locus of control or fatalistic beliefs (Sattler, Kaiser, & Hittner, 2000). Other factors that may influence risk perception include community involvement and the behavior of other people in the same situation (Lindell & Perry, 2004; Peek & Mileti, 2002). Most research assessing warning message effectiveness has focused on natural and technological disasters (e.g., Riad, Norris, & Ruback, 1999; Sattler & Marshall, 2002; Smith-Jackson, 2006). Few studies have examined text or e- mail messages designed to notify campus communities of active shooters or other emergencies (e.g., earthquakes, tornadoes). The current study extends past research by assessing text and warning messages concerning an active shooter on campus. An active shooter is a person who appears to be actively engaged in killing or attempting to kill people in a populated area; in most cases active shooters use firearm(s) and there is no pattern or method to their selection of victims. These situations are dynamic and evolve rapidly, demanding immediate deployment of law enforcement resources to stop the shooting and mitigate harm to innocent victims (Indiana University Police Department, 2009). Because these situations are dynamic and evolve rapidly, university communications offices, the university police department, or other appropriate departments will be required to quickly write coherent messages. However, it can take time to write and edit the information to fit within the 160 character limit for text messages. Furthermore, because clarity and accuracy of the information are essential, it would be beneficial to know whether students, faculty, and staff interpret and understand the information in the messages (via a pilot study). The authors of this study and the Emergency Management Committee at Western Washington University have prewritten text and message templates, based on recommendations by police officials, emergency management departments at universities across the country, and disaster researchers (Lindell &
5 Sattler et al.: Evaluating Text and Warning Messages 3 Perry, 2004; Peek & Mileti, 2002). The messages were written over a period of months and underwent numerous revisions. Table 1 presents these templates and shows that more information about an incident is presented based on the anticipated developments. The messages include specific information concerning the location of the incident and recommended actions students, faculty, and staff should take. In addition to assessing the clarity and comprehensibility of these text and messages, this study also evaluates the relationships among demographic characteristics, perception of risk, trust, locus of control, experience with disasters, self-efficacy, comprehension of the message, and predicted action the individual might take in response to the message. Although the messages contain more characters and words than the text messages, both include the same critical information. We expected that the text messages and messages would effectively convey the critical features of the situation and protective actions to take. Based on past research, we expected that self-efficacy, internal locus of control, greater experience with emergencies, higher trust in the source, and perceiving a higher risk in the situation would be positively associated with intent to take protective actions and actions consistent with the message content. Design and Participants Method The design was a 2 (Delivery type: cell phone text message, message) x 6 (Message content: serious threat on campus, serious threat on campus and leave the area, serious threat on campus and stay in the location ( shelter in place ), an active shooter on campus, update to the situation, and the situation is resolved) between-subjects analysis of variance (ANOVA). The participants were 264 (76 men, 188 women) undergraduate students at Western Washington University. The average age was 19.3 years (SD = 2.3). Most participants were Euro American, (81%), not married (97%), and did not have children (99%). About half had training in CPR, first aid, or lifesaving (54%) and about one-third (30%) had experienced a life threatening event. Materials A consent form described the purposes of the study, and all materials were printed on 8 1/2 x 11 paper. In the text message conditions, participants saw a large image of a cell phone with the text message presented within the cell phone. In the conditions, participants saw a large image of a computer monitor with the message presented within the monitor. Table 1 shows the and Published by Berkeley Electronic Press, 2011
6 4 JHSEM: Vol. 8 , No. 1, Article 41 text messages. After reading the message, participants answered questions presented in the following sections on a survey. Demographic characteristics. Nine items asked for demographic information, training in CPR, First Aid, or Lifesaving, knowledge about campus shootings, and experience with a life threatening situation. Participants indicated their answers by checking a box or writing their answer. Message clarity. Twenty-four items assessed the clarity and comprehensibility of information presented in the messages. Examples of the items include, The message says watch for updates; The message says to avoid all windows; and The message says Police are on the scene. Participants used a 2-point no/yes scale to indicate their answers. Feelings of trust, control, self-efficacy, and perceptions of risk. Eighteen items asked participants to indicate their reactions if they received the message during an emergency. Examples include, "Would you think the threat is serious?, Would you feel like you have control in this situation?, and How much emotional distress do you think you would feel? Participants used a 5-point scale (1 = not at all to 5 = very much) to indicate their answers. Actions in response to the message if participants were at the location of the incident. Sixteen items asked about actions participants predicted they would take if they were in the dangerous location when they received the message. Examples include, I would call the police, I would avoid all windows, and I would not know what to do. Participants used a 5-point scale (1 = not at all to 5 = very much) to indicate their answers. Actions in response to the message if participants were not at the location of the incident. The same 16 items from the previous section asked about actions participants predicted they would take if they were not at scene of the incident when they received the message. Cell phone use and familiarity with the University Alert System. Five items asked participants if they had a cell phone, if their cell phone receives text messages when on campus, if they had registered their cell phone number with the University Alert System, if they take their phone to class and leave it on during class, and if their phone alerts them when a text message is received. Participants used a 2-point no/yes scale to indicate their answers. use and computer access on campus. Five items asked participants to estimate what percentage of buildings on campus their phone worked in, how many hours a day they are on a computer, how often they check their , how often they visit the University s website, and if they bring a laptop to class. Participants also were asked to anticipate how often they would check the University website for updates if they received a text or about an ongoing active shooter situation. Participants wrote in a number to answer each question.
7 Sattler et al.: Evaluating Text and Warning Messages 5 Procedure Participants completed the survey in their classes. All responses were anonymous and confidential. It took approximately 15 minutes to complete the survey. Participants were debriefed and any questions were answered. The project was approved by the Western Washington University Human Participants Review Committee. Results Access to Cell Phones and on Campus Almost all participants had a cell phone (99%), were able to receive text messages (99%), were registered with the Western Washington University alert system (65%), take their cell phone to class (98.4%), leave their cell phone on during class (88%), and set their cell phone to alert them when they receive a text message (88%). On average, participants estimated they had cell phone service in most campus buildings (77%, SD = 17.27), indicated they spend 3.3 (SD = 3.1) hours per school day on a computer, check their 3 (SD = 2.5) times per school day, and visit the university website 3.15 (SD = 6.9) times per school day. About one-tenth (11%) used a laptop in class. Participants reported they would check the university website for updates every 23 (SD = 49) minutes if they received the alert via text message and every 23 (SD = 40.3) minutes if they received the alert via . Text and Message Comprehensibility Text message comprehension. Table 1 shows that for the text messages, the vast majority of participants understood the degree of threat, the actions to be taken, and that they should not reply to the text message. However, on average, only about two-thirds (63%) correctly understood that INFO: emergency.wwu.edu indicated updates would be presented on the website. Thus, we suggest to use UPDATES rather than INFO to clearly convey the intent. message comprehension. Table 1 shows that for the all messages, the vast majority (96% or greater) understood each component of the message. These messages also specifically indicated to check a website for updates. However, the all clear message appeared to convey two contradictory statements. One component indicated the campus is safe but another component indicated to stay away from the location of the incident. For this message, about two-thirds (67%) believed the campus was safe. Table 2 presents the actions Published by Berkeley Electronic Press, 2011
8 6 JHSEM: Vol. 8 , No. 1, Article 41 participants indicated they would take even though these actions were not indicated in either the text or messages. Table 1. Percentage who Correctly Understood Content of Text and Warning Messages (N = 264). Situation Message Content Percent Status Correct Text Messages Serious WWU ALERT. Serious threat at Smith Hall. 98% Threat Watch 4 updates. Info: emergency.wwu.edu Dont reply Serious WWU ALERT. Serious treat. Leave Smith Hall 99% Threat: now. Stay away. Watch 4 updates. Leave Area Info: emergency.wwu.edu Dont reply Serious WWU ALERT. Serious threat at Smith Hall. 98% Threat: Stay Stay away. If at location go 2 room/barricade in Room door. Info: emergency.wwu.edu Dont reply Active WWU ALERT. Shooter at Smith Hall. If on 96% Shooter campus go 2 room/barricade door. Dont come on Campus 2 campus. Info: emergency.wwu.edu Dont reply Active WWU ALERT. Shooter contained at Smith Hall. 94% Shooter If on campus stay in place. Dont come 2 campus. Update Info: emergency.wwu.edu Dont reply All WWU ALERT. Police believe campus now safe. 94% Clear Stay away from Smith Hall. Classes cancelled. Info: emergency.wwu.edu Dont reply Note. Only two-thirds (63%) of participants correctly interpreted INFO: emergency.wwu.edu as indicating updates would be presented on this website. We recommend replacing the word INFO with UPDATES to clarify the intent. Note: Table presents fictitious building name.
9 Sattler et al.: Evaluating Text and Warning Messages 7 Messages Serious There is a serious threat currently at Smith Hall. 96% Threat Police are evaluating the situation. Watch for updates. WWU will provide updates via: your , a text message to your cell phone (if you previously subscribed), websites. First, go to emergency.wwu.edu, then go to the WWU homepage, Serious There is a serious threat currently at Smith Hall. Police 99% Threat: are on the scene. Stay away from that location. If you Leave are in that location, leave immediately. Watch for updates. Area WWU will provide updates via: your , a text message to your cell phone (if you previously subscribed), websites. First, go to emergency.wwu.edu, then go to the WWU homepage, Serious There is a serious threat currently at Smith Hall. Police 96% Threat: Stay are on the scene. If you are in that location, stay in or in Room find a room. Lock or barricade the door. Avoid all windows. If you are not at that location, stay away from that location. Watch for updates. WWU will provide updates via: your , a text message to your cell phone (if you previously subscribed), websites. First, go to emergency.wwu.edu, then go to the WWU homepage, Active There is a shooter on campus at Smith Hall. You are at 99% Shooter serious risk. Police are on the scene. If you are on on Campus campus, stay in or find a room. Lock or barricade the door. Avoid all windows. Classes are cancelled until further notice. WWU will provide updates via: your , a text message to your cell phone (if you previously subscribed), websites. First, go to emergency.wwu.edu, then go to the WWU homepage, Active The shooter at Smith Hall has been contained. Stay away 97% Shooter from that location. Police are on the scene. If you are on Update campus, please remain where you are until the situation is resolved. If you are off campus, do not come to campus. Classes are cancelled until further notice. WWU will Published by Berkeley Electronic Press, 2011
10 8 JHSEM: Vol. 8 , No. 1, Article 41 provide updates via: your , a text message to your cell phone (if you previously subscribed), websites. First, go to emergency.wwu.edu, then go to the WWU homepage, All Today, there was a situation involving a shooter at WWU. 98% Clear Police have resolved this situation and are investigating. Police believe the campus is now safe. Stay away from Smith Hall as police investigate. If you are off campus, do not come to campus. Classes remain cancelled until further notice. WWU will provide updates via: your , a text message to your cell phone (if you previously subscribed), websites. First, go to emergency.wwu.edu, then go to the WWU homepage, Intent to Comply with Message Instructions Table 3 shows that participants receiving the text message indicated they would take all of the actions indicated in the message, as well as additional protective actions that were not indicated in the text message, such as checking and text messages for updates. Table 3 also shows that participants receiving the e- message indicated they would take all of the actions indicated in the messages, as well as additional protective actions that were not indicated in the message, such as avoiding windows, locking or barricading the door, and not replying to the message. Factor Analysis on Actions in Response to the Message Items A principle component factor analysis with varimax rotation was performed on the 16 items asking about actions participants might take in response to the message. Four factors with eigenvalues greater than one and with factor loadings greater than.60 emerged. Factor one assessed trust and quality of the message (α =.79) and included three items: Do the instructions in the message seem appropriate to you?, Would you trust those responsible for sending the message?, and Does the message provide enough information about the situation for you to make a good decision about what to do? Factor two assessed risk perception and distress (α =.76) and included three items: Would you feel at risk if you were in the location specified in the message?, Would you think the threat is serious?, and How much emotional distress would you feel?
11 Sattler et al.: Evaluating Text and Warning Messages 9 Table 2. Intent to Take Actions that Were Not Described in the Message if Individual was at Incident Location (N = 264). Note: Means presented. Rating scale: 1 = not at all likely to take this action to 5 = very likely to take this action. Message Serious Threat Serious Threat: Leave Area Serious Threat: Stay in Room Active Shooter on Campus Active Shooter Update All Clear Action Text Text Text Text Text Text Ask nearest person what to do Follow what other people do Hide under the nearest table/desk Not know what to do Call a friend or family member Call the Police Published by Berkeley Electronic Press, 2011
12 10 JHSEM: Vol. 8 , No. 1, Article 41 Table 3. Intent to Take Actions that Were and Were Not Described in Message if Individual was at Incident Location (N = 264). Note: Means presented. * = Message indicates take this action; No * = Message did not indicate the action. Rating scale: 1 = not at all likely to take this action to 5 = very likely to take this action. Message Serious Threat Serious Threat: Leave Area Serious Threat: Stay in Room Active Shooter on Campus Active Shooter Update All Clear Action Text Text Text Text Text Text Leave the building immediately * 3.92* Watch for updates 4.10* 3.83* 4.14* 3.58* * Stay in the room * 4.14* 3.86* 4.04* 3.85* Lock or barricade the door * 4.38* 4.68* 4.82* Avoid all windows * * Do not reply to the message Check for updates Check phone for text updates 4.67* * * * * * * * * * * * * * * * * * Check website * * * * * *
13 Sattler et al.: Evaluating Text and Warning Messages 11 Factor three assessed perceived control, self-efficacy, and ability to handle the situation (α =.76) and included three items: How confident would you be in your ability to handle this situation?, Would you know what to do in this situation?, and Would you feel like you have control in this situation? Factor four assessed external locus of control (α =.32) and included three items: Do you believe it is not always good to plan too far ahead because many things happen because of good or bad fortune?, Do you think it is likely that you may receive a message like this one this year?, and Do you believe that when you get what you want it is usually because you are lucky? The first three factors had adequate reliability and the fourth factor had poor reliability. Analysis of Variance Tests Two-way between-subjects (Delivery Type x Message Content) ANOVA tests assessed the quality of the each message, perceptions of threat and distress, and perceived ability to control or handle the situation, and Tukey post-hoc comparisons were performed when appropriate. Trust and quality of message. There was a main effect of message content on message reliability, F (5, 248) = 8.96, p <.001, MSE =.736, eta 2 =.153. The active shooter on campus message resulted in the highest level of trust and quality, followed by active shooter update, serious threat-stay in room, serious threat-leave, all clear, and serious threat. Threat/distress. There was a main effect of message content on risk perception and distress, F (5, 248) = 8.96, p <.001, MSE =.495, eta 2 =.124. The active shooter on campus message was associated with more risk perception and distress than the serious threat message. The serious threat-stay in room, the active shooter on campus, and the active shooter update message were associated with more risk perception and distress than the all clear message. Control/handle situation. There was a main effect of message content on perceived control and ability to handle the situation, F (5, 248) = 3.27, p =.007, MSE =.718, eta 2 =.062. Participants felt as though they had more control and were better able to handle the situation when presented with the serious threatstay in room message, the active shooter update message, and the all clear message rather than the serious threat message. Correlations Table 4 shows that message reliability and trust were strongly associated with believing that the message provided enough information, being likely to comply Published by Berkeley Electronic Press, 2011
14 12 JHSEM: Vol. 8 , No. 1, Article 41 with the message, and feeling able to control or handle the situation. Likelihood to comply with the message was strongly associated with feeling that the message provided enough information. Feeling able to handle or control the situation was associated with being likely to comply and feeling like the message provided enough information. Having training in First Aid/CPR was weakly associated with perceiving a threat and feeling distressed, and negatively associated with their ability to handle or control the situation. Table 4. Correlations among Gender, Training, Experience, Message Reliability, Threat Perception, Ability to Control Situation, External Locus of Control, Likelihood to Comply, and Message Information (N = 264). Variable Gender Training in first aid/cpr 3. Experience with other life threatening events 4. Message reliability 5. Treat and distress 6. Ability to control or handle situation 7. External locus of control 8. Likely to comply with message 9. Message provides adequate information **.19** * -- Note: * = p <.05; ** = p < **.17**.18**.23** ** ** **.61**.34**.31** **.21**.44** ** Discussion Almost all participants (95%) understood the text and messages and indicated they would comply with the recommended self-protective actions. A small percent indicated they might take additional precautionary actions that were not discussed in the message, such as hiding under a desk, calling a friend or
15 Sattler et al.: Evaluating Text and Warning Messages 13 family member, and following the actions of other people. Participants who received the serious threat and active shooter update messages also indicated they would lock or barricade the door and avoid windows, even though these actions were not discussed in the messages. Message reliability and trust were strongly associated with likelihood to comply with the message and feeling able to control or handle the situation. Likelihood to comply with the message was strongly associated with feeling that the message provided enough information. This is consistent with prior research. Trusting the message source increases a person s compliance with instructions (Mileti & Peek, 2002). Effective messages (a) describe the situation clearly so that people understand the danger, (b) are issued by a credible source, (c) include specific information indicating the location and time of the event, and (d) state protective actions (Mileti & O Brien, 1992; Mileti & Peek, 2000). The present results indicate the messages effectively addressed each of these components in the context of an active shooter situation. Almost all (99%) students reported having a cell phone, that they leave it on during class, and that the phone alerts them when a text message is received (88%). Although most students indicated that they check their several times throughout the day, only about one-tenth bring a laptop to class. These findings suggest text messaging may be one of the most important mediums to immediately notify students of an incident (cf. Junco & Cole-Avent, 2008). In order to receive a text message, however, students must register their cell phone number with the college or university. About two-thirds of students in this study reported having registered with the Western Washington University alert system database, and the University states that 82% of all students have registered with the system. Because the effectiveness of the warning system depends upon the percent of persons having preregistered with the system, institutions should take special effort to register students, faculty, and staff. Effectiveness also depends upon cell phone coverage and reception. Most cellular phone companies state that they cannot guarantee reception within buildings, and it is likely that cell phone service may be sporadic or unavailable in certain buildings. There also are concerns whether the cell phone company can process and send thousands of text messages in a timely manner. Text messages are limited to 160 characters or less and this limitation means that careful thought is needed when crafting a clear, concise, and complete message that will result in the desired response from the recipients. The Western Washington University Emergency Management Committee developed the templates presented in this study to be used during an event, with the understanding that they can be modified if needed. Having the template and assessing the effectiveness of each message allows the Committee to revise components of messages that were not completely clear, such as how to get Published by Berkeley Electronic Press, 2011
16 14 JHSEM: Vol. 8 , No. 1, Article 41 additional information. Having templates will significantly reduce the amount of time needed to construct an effective message during a crisis situation. Higher education institutions also can prepare text and templates for other types of mass emergencies or disasters, including earthquakes, tornadoes, and hurricanes. Using the methodology presented in this study will provide critical feedback to aid Committees in assessing the clarity and effectiveness of the messages and in subsequent message revisions. One limitation of this approach is that participants received the message on paper during a study rather than on their cell phone or , and actual behavior during an emergency might differ. Future research should examine how people of various age groups and positions across the university respond to the messages, and might deliver the messages during a simulated emergency in order to study in more detail compliance with the message. Effective text and messages may minimize loss of life and injury by keeping the campus community informed as an incident develops. References Indiana University Police Department (2009). Responding to an active shooter. Jeanne Clery Disclosure of Campus Security Policy and Campus Crime Statistics Act (2008), Public Law ; U.S. Department of Education, Junco, R. and Cole-Avent, G. A., (2008). An introduction to technologies commonly used by college students. New Directions for Student Services, 124, Lindell, M. K. and Perry, R. W. (2004). Communicating Environmental Risk in Multiethnic Communities. Thousand Oaks, CA: Sage Publications, Inc. Mileti, D., & O'Brien, P. (1992). Warnings during disaster: Normalizing communicated risk. Social Problems, 39, Mileti, D. S., & Peek, L. (2000) The social psychology of public response to warning of a nuclear power plant accident. Journal of Hazardous Materials, 75, Peek, L. A., & Mileti, D. S. (2002). The history and future of disaster research. In R. B. Bechtel & A. Churchman (Eds.), Handbook of Environmental Psychology (pp ). NY: John Wiley and Sons. Plummer, D., & Johnson, W. (2008). Planning for Battle. American School and University, 80(7), Riad, J. K., Norris, F. H., & Ruback, R. B. (1999). Predicting evacuation in two major disasters: Risk perception, social influence, and access to resources. Journal of Applied Social Psychology, 29,
17 Sattler et al.: Evaluating Text and Warning Messages 15 Sattler, D. N., Kaiser, C. F., & Hittner, J. B. (2000). Disaster preparedness: Relationships among prior experience, personal characteristics, and distress. Journal of Applied Social Psychology, 30, Sattler, D. N., & Marshall, A. (2002). Hurricane preparedness: Improving television hurricane watch and warning graphics. International Journal of Mass Emergencies and Disasters,20, Sjöberg, L. (2000). Factors in risk perception. Risk Analysis, 20, Smith-Jackson, T. L. (2006). Receiver characteristics. In M. S. Wogalter (Ed.), Handbook of warnings (pp ). Mahwah, NJ: Lawrence Erlbaum. U.S. Department of Education (2008). Campus Security. Retrieved May 6, 2009, from U.S. Department of Education Web site: Published by Berkeley Electronic Press, 2011
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