Start with the first sentence.

In recent years, various organizations in different countries have established campaigns in which people are challenged to give up alcohol for 1 month. Some are designed as sponsored fundraising events (e.g.,, Others such as “Dry January” ( are simply presented as a challenge to be undertaken in cultures in which alcohol consumption is a common feature of social life (Babor, 2010).

If you are not familiar with this challenge tactic, check the Dry January website and poke around a minute. It is what it says it is: A challenge to stop drinking for a month, specifically, January, although I believe you can take the challenge anytime. This screenshot will give us a quick overview of Dry January.

Dry January Landing Page

Observe the ubiquitous SM2.0 icons. Then read the menu ribbon. You can get a special app, advice, and fundraising which is not what you think it is. Fundraising means if you sign up for Dry January, you can also seek out Other Guys who will contribute money to charitable causes if you participate. Also, the program encourages Other Guys to buddy up with a partner who also signs up for the program.

Stop now and consider this. I call it a MOP, Massively Online Persuasion. Other Guys learn about Dry January through a variety of media sources and then visit the site. All the persuasion happens through and with the website. Some Other Guys sign up for the challenge. Among them, some get friends and family to make a financial contribution contingent upon participation. Some buddy up with a friend and take the challenge together. Do you see any persuasion principles in with this MOP?

Sure, a bunch of Cues. Start with Commitment/Consistency. When the Other Guys sign up, they are making a commitment. That commitment gets enhanced when the Other Guys also attract financial sponsors or buddy up. As the Cue states: When You Take A Stand, You Must Stay Consistent With It. Those sponsors and partners build the commitment and enhance the need for consistency.

See, too, Reciprocity, but in a very clever way. Normally, reciprocity operates when you give the Other Guy something which, by social norms, requires them to give you something back. Typically, you win the exchange by giving less than you get in return because the Other Guy feels the heat from Uncle Norm to make an exaggerated display of conformity and politeness. With Dry January, reciprocity operates differently.

The Guy signing up is giving someone else something: Sobriety for a month. The Other Guy in return reciprocates with money for a charity. The buddy reciprocates with her sobriety. But, what this reciprocity does is create a Skinner Box for the person doing Dry January. If she fails to complete the 30 days, she breaks her initial “gift” of sobriety. That releases the Other Guy from making the charitable contribution and could also release the buddy from abstaining; you see the psychological punishment. The Dry January Guy made a commitment and dragged Other Guys and their money and reputation or will power and self control as Other Guys into this game. Failure embarrasses all involved.

Most generally, we are seeing the effects of making a choice with social connections as a bonus. This is a hot house for Dissonance and Balance and all those consistency theories. People like to see themselves as consistent in thought and deed and relationship. When you make a choice with Dry January, you have opened a Pandora’s box of potential pressure.

And then you have the social pressure of doing Dry January with a friend also doing Dry January. You make more commitments here. You’ve got some reciprocity going. And, you’ve got the Liking Cue going with the affection from a relationship driving behavior.

But, none of this is immediately apparent in the Dry January website. I’m also not sure after reading about the program whether the inventors realize what’s going on. It’s just another one of those challenges with a run for life charity fundraiser. But, even if the people running Dry January do not realize the persuasion running under the surface, the tide is there.

But, does this work? Consider an evaluation study.

Participants. The baseline sample consisted of 1,070 men and 2,722 women aged 18 years or older (range = 18–76, median = 41, M = 40.7, SD = 11.6) who had registered on the Dry January web site. Data from an additional 411 people were excluded from analysis: 11 respondents aged under 18 years; 10 people who had not consumed alcohol in the past year; 84 people who did not live in the United Kingdom; and 306 who did not complete the baseline questionnaire. One-month follow-up data were provided by 1,684 people (479 men, 1,205 women; 44.4% of original eligible sample). Six-month follow-up data were provided by 857 people (249 men, 608 women; 22.6% of original eligible sample). Only the 857 respondents who completed all three waves of data collection were included in the analyses presented here.

The surveys collect primary data on the past and current drinking behavior of the Other Guys with three key self report items on drinking frequency, amount, and bingeing.

[Omission Sidebar: The researchers also collect reports on self-efficacy, that sense of self mastery and control. If you are interested in this variable, please read the paper. I will omit the results because I want to focus on the website and drinking behavior. End of Omission Sidebar.]

They also count how long the Other Guy stays dry during January.

In response to the question “How many days after registering for Dry January did you have your first alcohol-containing drink?,” participants indicated the number of days from the start of Dry January until they first consumed alcohol (in days, weeks, and/or months). Their responses were used to create a dichotomous variable that indicated whether they had successfully completed Dry January (Completed Dry January).

This is a repeated measures observational study. About 3,700 Other Guys sign up at the Dry January site and are asked to complete surveys as part of their participation. Surveys are run at baseline, 1 month, and 6 months. While we start with 3,700, only 857 Other Guys complete all three waves and get counted.

Right. We lose nearly 3 of 4 starters. Attrition like this is always a counting nightmare because you don’t know how it is biasing the results. You can make comparisons on the baseline survey between those who went all the way and those who dropped out, but you never know for sure what’s going on. And, if you read the details carefully you know that among the 3,700 who started 400 didn’t even do the baseline, so you’ve got no information about 10% of the starters anyway. This is almost always a problem with observational field studies. There is no good solution and you always need to keep your mind on a swivel when you consider the results. Professor Poopypants has cautioned! On with the opera!

Count the change that counts: Drinking behavior. Here’s the main table of results.

Dry January Table of Results

The Table is self explanatory. By column you see the dependent variable, baseline and 6 month follow up means, then the difference and effect size. The top half tracks the 549 who made 31 dry days, the bottom half is the 308 who did not. Note my red highlights on the change I think counts the most with self reported drinking behavior.

As you can see by comparing the Cohen’s d effect sizes (0.2 is Small, 0.5 Medium, and 0.8 Large), there were Small to Medium Windowpanes in self reported drinking and in the correct direction, less of it. But then you see a wrinkle. There’s no difference in reduced drinking between those who went dry for 31 days and those who did not.

Look again at the Table of results and you’ll see that there is little difference in the amount of change between the two groups of participants over time. I ran t-tests on the change for the two groups on each of the three drinking variables. I compared those who completed versus those who did not on the three drinking variables. None of the t-tests were even statistically significant with over 800 cases.

Now. You can see that the completers have lower drinking scores at baseline that are statistically significant with Small Windowpanes. And they also have lower drinking scores at 6 months. But, the amount of change from base to 6 months is the same for both groups.

I see two key headlines: 1) The completers were drinking less to begin with, and 2) Everyone drank less.

It appears thus that this iIntervention works. Build a website that has the characteristics of a persuasion engine. Drive Other Guys to the website with media plays – ads, news stories, radio interviews, whatever. If the Other Guy signs up, then they will change. The MOP works at a Medium Windowpane, a practical and obvious difference.


I am nervous about this evaluation and dubious about the validity of the results. The count is true. Any Other Guy who signed up for Dry January reported less drinking six months after the challenge. But, does the count mean what it seems? Consider several challenges to interpretation.

Remember that we lost 3 of 4 starters. That is a terrible attrition rate and inevitably produces bias in the remainder. Worse still, there is no way to know exactly how the bias operates.

Self reports on addictive substances like drugs, alcohol, and tobacco are always suspect. Such Other Guys always miscount their behavior. Always. And, almost always in the most favorable way. They think and say they are doing better. Then when you do chemical tests on them, the change usually drops like a rock in a pond. There is simply no independent verification of these counts. Here’s another way to think about this.

If you read the paper you’ll notice something missing. The researchers do not report any correlations between the MOP and the drinking behavior reports. For example, the researchers could have counted how often or how much Other Guys visited the Dry January website or app or any other online pages. They could have then correlated these “persuasion dose” indicators with self reports on drinking. One would expect that Other Guys who used the MOP more should drink less. But, the paper contains no such information. Why not? That would provide a better kind of proof (for me, at any rate) than simply taking self reports of substance abuse at face value.

I’m also leery about seeing a change on a behavior like this that lasts 6 months. All the persuasion from Dry January is running on the Peripheral Route with Cues from consistency, reciprocity, liking, and so on. There’s no presentation of Arguments with the Long Conversation in the Head as with the Central Route. And we know that Peripheral Route change can produce as much immediate change as the Central Route, but it rarely produces a change that lasts over a long time period. A decrease in drinking that holds for 6 months is a long change.

When you put these data within the large literature on persuasion and substance abuse along with the smaller, but growing, literature on MOPs or iInterventions or whatever clever label you can invent, you have more questions than answers. Yes, I believe the numbers in the paper are accurate and reflect what was in the database. But, how those numbers got in the database and what they mean is tricky.

To the researchers’ credit, they do not over-claim their data and hail this as a cure for alcohol abuse. They note many of the limitations we’ve examined and add others, like the absence of a control group, to consider. I think we must remember that we are dealing with a TACT that can have life and death implications. We need to hit stronger standards of science before we make any conclusions. Dry January does not appear to make things worse for Other Guys, but it also does not appear to make things better, either.

Everyone is in the bag for apps ‘n iGizmos as if technology will by itself Make The World A Better Place. Technology is not persuasion nor does technology remove the need for strong methods of evaluation. Right now, most digital operations are running on the cheap, trying to do the weakest science they can get away with. When you read studies about MOPs you see Big Data, but you don’t often see: Random selection and assignment; controlled conditions; strong comparisons; careful counting; replication; or a theory base. As we often observe, most of the persuasion coming from the Internet is aimed at persuading Other Guys the Internet is persuasive rather than proving that the Internet is persuading Other Guys.

This is a complicated Local. Alcohol abuse is nearly as deadly as smoking, so any improvements you can persuade is important. Yet, that deadly importance can permit a Sincere desire to create improvement without the cold heart and mind of a panther or a scientist trying to prove whether something truly works. Dry January may make people feel good about themselves and attract a lot of favorable and foolish media Buzz, but the count just isn’t there.

de Visser, R. O., Robinson, E., & Bond, R. (2016). Voluntary temporary abstinence from alcohol during ‘Dry January’ and subsequent alcohol use. Health Psychology, 35(3), 281-289.