Reach of Early Warning System

Output

Outcome

% of households who received an early warning message during or immediately before [specify the hazard / event]

The indicator measures the proportion of households in target areas that received an official early warning message during a hazard event or an early warning system test, either directly or indirectly, through any communication channel. It helps assess how well warning messages reached people at risk through the communication channels used by the early warning system.

Determine the indicator’s value by using the following methodology:

 

1) Soon after the hazard event or early warning test, conduct a household survey with a representative sample of the target households. Make sure respondents clearly understand which event you are referring to.

Ask whether anyone in the household received an early warning message during the event. Use simple wording so respondents clearly understand what is meant. Example of recommended question:

RECOMMENDED SURVEY QUESTION (Q) AND POSSIBLE ANSWERS (A)

Q1: “During or immediately before [specify hazard/event] did anyone in your household receive a message warning you about it?”

A1: Answer options (adapt to your context):

• Yes, directly (e.g., SMS from the official system, radio, or loudspeaker)

• Yes, indirectly (e.g., informed by family, neighbour, friend)

• No

• Don’t remember

 

2) To calculate the indicator’s value, divide the total number of households that reported receiving a warning message (regardless of the source) by the total number of surveyed households, excluding “don’t remember” responses. Multiply by 100 to convert it to a percentage.

Disaggregate by gender of the head of household, location, type of hazards, type of communication channels (direct vs indirect) and other relevant criteria such as disability status, phone ownership, and language spoken, where feasible.

1) Conduct this survey as soon as practical after the event (ideally within 1-3 weeks) while memories are fresh. Longer delays reduce recall reliability.

2) If relevant for your intervention, also ask from whom the message was received, as this helps identify which communication channels were used.

Q2: “From whom did you receive the message?”

A2: Answer options (adapt to your context):

• Official Early Warning System (e.g. government SMS, automated call, siren, radio broadcast)

• Community-based warning (e.g. village committee, volunteer, local leader)

• Family, neighbour, or friend

• Social media (e.g. Messenger, WhatsApp, Telegram)

• Other (specify)

• Don’t remember

3) For hazards like floods, cyclones, or volcanic eruptions, lead time is essential for evacuation and asset protection. Consider asking whether the message was received early enough to take action. Example of recommended question:

Q3: "Did your household receive the warning with enough time to take protective action?"

A3: Yes / No / Don’t remember

4) Distinguish direct communication (e.g. SMS, radio, siren, official loudspeaker) from indirect information (e.g. word of mouth via neighbours, family, community members), as these have different implications for attribution, reliability and inclusiveness.

5) If you can afford a sufficiently large sample to be able to get reliable results even for smaller population groups, we recommend that you analyse which communication channels reach different groups most effectively. Differences by disability status, language, phone ownership, remoteness, or social position may indicate barriers to access and should be documented where observed.

6) When possible, verify survey results against official data (e.g. SMS delivery lists, broadcast coverage, or system registers).

7) For a fuller picture, also consider using this indicator together with the effectiveness of early warning messages indicator to assess not only reach but also action.