Subword and Spatiotemporal Models for Identifying Actionable Information in Haitian Kreyol

Crisis-affected populations are often able to maintain digital communications but in a sudden-onset crisis any aid organizations will have the least free resources to process such communications. Information that aid agencies can actually act on, 'actionable' information, will be sparse so there is great potential to (semi)automatically identify actionable communications. However, there are hurdles as the languages spoken will often be under-resourced, have orthographic variation, and the precise definition of 'actionable' will be response-specific and evolving. We present a novel system that addresses this, drawing on 40,000 emergency text messages sent in Haiti following the January 12, 2010 earthquake, predominantly in Haitian Kreyol. We show that keyword/ngram-based models using streaming MaxEnt achieve up to F=0.21 accuracy. Further, we find current state-of-the-art subword models increase this substantially to F=0.33 accuracy, while modeling the spatial, temporal, topic and source contexts of the messages can increase this to a very accurate F=0.86 over direct text messages and F=0.90-0.97 over social media, making it a viable strategy for message prioritization.