Yesterday I aggregated some data from Twitter that referenced KFC, Nandos, Debonairs or McDonalds and sat with the Mobenzi pilot participants as we answered two simple questions about each tweet.

1. Was the message positive, negative or neutral in reference to the brand?
2. If it was negative, was it due to customer service, taste, health or some other reason?

The work was entertaining for the participants, they completed tasks efficiently and the results seem to be very accurate.

About sentiment analysis

With the growing use of online services like Twitter, blogs and forums, there is a vast amount of publicly available information generated by everyday people about millions of different topics (companies, products, movies etc.). Knowing the sentiment of messages (e.g. whether they are positive or negative) can be extremely valuable to the people or organisations involved, especially when monitoring trends over time.

Sentiment analysis or opinion mining refers to a broad area of natural language processing, computational linguistics and text mining. Generally speaking, it aims to determine the attitude of a speaker or a writer with respect to some topic.

The rise of social media such as blogs and social networks has fuelled interest in sentiment analysis. With the proliferation of reviews, ratings, recommendations and other forms of online expression, online opinion has turned into a kind of virtual currency for businesses looking to market their products, identify new opportunities and manage their reputations.

Find out more about sentiment analysis on Wikipedia

This kind of work is well suited to Mobenzi agents

Sentiment analysis seemed like a very appropriate type of task for processing by Mobenzi agents on their phones as tweets are very short (only 140 characters). We also felt that there would be a demand for an efficient human sentiment rating service since computer algorithms face many difficulties in trying to understand the tone of human messages.

Twitter includes a lot of slang, humour, Textese and other informal language that makes automated analysis especially difficult. In a multi-cultural country like South Africa, many tweets also combine words from a variety of local languages which would make analysis very challenging to a computer.

Example Tweets that reference take-out brands

These were some of the messages included in our sample set of data from Twitter.

"Damn you debonairs" in this context is meant in jest and is not negative.

The sentiment is not obvious in this message.

The tone in this tweet changes totally at the end of the message.

The results were ‘positive’

The focus of this study was to assess issues relating to the completion of tasks. We only looked at a small sample of tweets, and could have been a lot more scientific in our approach, so the sentiment results themselves should not be taken too seriously.

There were six participants (including myself) and we each stepped through the analysis of Twitter messages that mentioned KFC, Nandos, Debonairs or McDonalds. Each task took only a few seconds to complete and the team found the work interesting and engaging. None of the participants (except myself) use Twitter themselves, but they were all very familiar with the concept and frequently use Mxit which is similar in some aspects.

One of the measurements we look at to gauge the accuracy of results, is the agreement between different participants for the same task. All six participants rated the sentiment of each tweet, so we were able to look at where our answers differed. It was very encouraging to see that most answers had 100% agreement (Especially if we exclude where participants stated that they were unsure of the sentiment). There are only a few cases where we disagreed on whether a particular tweet was positive or negative. In these cases, the majority was correct and in some cases the disagreement actually helped to balance the rating where the sentiment was ambiguous.

The summary across all brands came out at 48% positive, 35% negative and 17% neutral or unclear. Of the negative tweets, 29% were service related, 16% to do with taste, 9% health related and the rest for other reasons.

These charts show the summary of the sentiment analysis for all four brands.

In the following results, we excluded tweets that were either neutral or unclear with regard to sentiment. Out of the four brands, Nandos was clearly the favourite with 80% of tweets being rated as positive.

Breakdown of Positive versus Negative sentiment for each brand

To have a look at what people are saying right now about these brands, simply go to www.twitter.com and search for #Nandos, Debonairs, #KFC or #Mcdonalds.

Interestingly, a quick analysis of these keywords on Tweetsentiments.com (A service that attempts to automate the analysis of tweets) returns fairly similar results in terms of rank, but with some significant variations in the actual sentiment rating. Nandos: 68% positive, Debonairs 59% positive, Mcdonalds 56% positive and KFC 52% positive. The ranking of the brands is the same as our result, except that Mcdonalds moved in front of KFC with the automated analysis. This may have to do with the fact that we only looked at tweets in English and other South African dialects. Perhaps English speaking people are the least positive about Mcdonalds? Looking at some of the tweets in their data sets, I would trust our result over the automated one. Try the service out yourself at  http://tweetsentiments.com/analyze

It is no coincidence that we ended up having Nandos and Debonairs for lunch.

Many organisations receive thousands of inbound SMS messages

SMS text messaging is the most widely used data application on the planet, with 2.4 billion active users (Wikipedia). A growing number of organisations are using text messages to communicate with mobile phone users. Although most communications involve distributing information to end users, many organisations receive and process thousands of text messages from end users.

Once an SMS is received by an organisation, its content needs to be analysed and understood to enable reporting or features such as sending a relevant reply SMS. Dealing with a large volume of inbound SMS messages requires automated processing (efficient sorting of messages) to save time and money. Processing these SMS messages manually is often not feasible.

It is difficult for computers to understand messages written by people

Using computer programs to automatically sort sms messages involves either extremely advanced natural language processing (NLP) or end users adopting a specified syntax in their messages (e.g. Sms your NAME, followed by your AGE and then the KEYWORD…) so that the messages can be more easily understood by a computer.

Natural language processing is extremely complex

Natural language processing (NLP) is a field of computer science and linguistics concerned with the interactions between computers and human (natural) languages. Natural language understanding systems convert samples of human language into more formal representations such as parse trees or first-order logic structures that are easier for computer programs to manipulate. (Wikipedia )

Although there are many services like Google SMS and WolframAlpha that make use of NLP concepts, I don’t believe that we will see a generic natural language understanding solution that we can use for SMS messages in the near future, especially one that would cater for the many languages in developing countries. Such systems would still require extensive customisation in order for a computer to understand the meaning of an SMS within a particular context.

Structured syntax is not easy to use

People have invested significantly in making operating systems, computer programs, websites and hardware easy and intuitive to use. For many people however, plain text sms messages are the only interface they will have to online services such as banking, classifieds and social networks for the next few years.

The process of interfacing to a software system via sms is often difficult. The common approach of using structured syntax messages (requiring users to adopt a set of words and rules in their messages) is comparable to entering instructions at the DOS command prompt like many of us used to do 20 years ago. Although the command line as an interface is having somewhat of a comeback (”The Web Browser Address Bar is the New Command Line“),  it is usually only expert users who really make use of most commands.

Many people make use of structured syntax commands with applications like Twitter (”RT” or “@username” ect.), Google (”1USD in ZAR“)  and other services like IRC. But with all of these applications, understanding the structured syntax is not required for new users or the majority of interactions. With many sms systems however, users are required to understand the syntax right from their first interaction. I think it is quite unnatural, unintuitive and difficult for many people to use fixed syntax commands, especially via SMS which is predominantly used for communication between people.

Organisations also need to communicate the rules and language of the system to mobile phone users so that they understand what words they can use and how to structure their messages. It is very difficult to do this via SMS due to limitations in the number of characters in an SMS and the cost of each message, especially if a sequence of messages is required.

Where there are only a few commands or keywords that need to be learned, using structured syntax can work very well. But when SMS systems start offering more interactive services, they will become much more difficult to design and to use.

Perhaps the biggest challenge with any computer based processing of SMS messages is that users often expect that a person will read and understand their message and therefore use informal language (Textese), ask questions or otherwise make spelling and grammatical errors.

People can help computers understand SMS messages

Certain processing tasks, such as understanding an SMS as described above, are still performed better and faster by humans than by computers. But manually processing inconsistently large volumes of such tasks is not feasible for internal staff at many organisations.

This problem inspired us to create Mobenzi, a service that allows organisations to outsource these kinds of tasks to a distributed team of workers who could share the load of many organisations’ processing requirements.

Mobenzi is a software service that empowers people to be rewarded for completing simple tasks on their mobile phones.

We are currently piloting the system and are confident that we will be able to take some live projects on within the next few months. Although there are several business applications we are addressing with Mobenzi, sorting of SMS data is our initial focus.

The concept of human intelligence tasks (simple tasks that computers find difficult) was first popularised by Amazon with their Mechanical Turk web service. We also recently came across Textonic that is attempting to leverage Mechanical Turk for tagging SMS messages in a similar way to Mobenzi. We hope that Mobenzi will be very well suited to processing SMS data since the processing itself can be done on a mobile phone by a Mobenzi agent who speaks the same language as those people sending the SMS messages. We plan on making it very easy to set up new teams of Mobenzi agents in new locations so that the agents will understand the local languages and colloquial terms that are included in the data that needs to be processed.

Mobenzi will allow computer programs that receive SMS messages to seamlessly interface to real people who can interpret free text messages and return information such as categories, tags, and other structured data as part of an automated process. Once an SMS is received by an organisation, the message can be submitted to Mobenzi for processing (via an API call for example). A Mobenzi agent would then be sent the original free text SMS with an associated form (see example below) to extract and structure the relevant information contained in the message – obvious to a human observer but inaccessible to computer systems.

This task illustrates how a simple natural language sms can be processed by a Mobenzi agent to extract structured data from the message.

Find out more about how Mobenzi works.

As part of the current pilot phase, we are assessing the cost and quality issues involved in the completion of tasks. We hope to make the processing service very affordable, especially considering that the requesting system can save costs in the long run through learning from the results generated by Mobenzi.

We hope that Mobenzi will help make many more online services available to people whose only interface to the internet is via SMS.

If you have any specific requirements you’d like to explore using Mobenzi for, please contact us.