Freedom had been hunted round the globe; reason was considered as rebellion; and the slavery of fear had made men afraid to think. But such is the irresistible nature of truth, that all it asks, and all it wants, is the liberty of appearing.
~ Thomas Paine, Rights of Man, 1791 ~

Sunday, April 23, 2017

How Effective Is Prayer?

Does Prayer work?

I've never met a Christadelphian who did not believe prayer was effective and worthwhile. This belief is probably one of the most widespread beliefs among all Christians, and people from other religions too. I used to pray, and I was convinced that at least some of my prayers were answered even though I couldn't be completely sure which ones.

Many believers pray every day, and even several times per day, so obviously they believe prayer really works. But have you ever thought about that? Does it actually work? How would you go about finding out? It's not enough just to think of a time when you prayed and something happened. You might be ignoring other times when nothing happened, or the statistical likelihood of that thing happening to any one person on the planet by chance alone. What about all of the other possible outcomes that you might have likewise interpreted as an answer to that same prayer?

What many believers may not be aware of is that prayer has been studied scientifically and there are even randomized, controlled trials that show a statistically significant positive benefit in favour of prayer! Let's have a look at some of the studies on prayer and what they found...

Can God be tested?

A very common Christian criticism of prayer studies is that God cannot (and should not) be tested. They quote verses such as Deuteronomy 6:16 which was also quoted by Jesus in Luke 4:12:
"You must not put the Lord your God to the test"
Deuteronomy 6:16 NET

However, it's not always that clear because the Bible also contains the following:
“Bring the entire tithe into the storehouse so that there may be food in my temple. Test me in this matter,” says the Lord who rules over all, “to see if I will not open for you the windows of heaven and pour out for you a blessing until there is no room for it all."
Malachi 3:10 NET (emphasis mine)

King Ahaz was actually rebuked by Isaiah for not wanting to test God, as we see in Isaiah 7:
The Lord again spoke to Ahaz: “Ask for a confirming sign from the Lord your God. You can even ask for something miraculous.” But Ahaz responded, “I don’t want to ask; I don’t want to put the Lord to a test.” So Isaiah replied, “Pay attention, family of David. Do you consider it too insignificant to try the patience of men? Is that why you are also trying the patience of my God? For this reason the sovereign master himself will give you a confirming sign.
Isaiah 7:10-14 NET
Dear friends, do not believe every spirit, but test the spirits to determine if they are from God, because many false prophets have gone out into the world.
1 John 4:1 NET

But there's a much better example of God being put to the test in the Bible.

That time when God was completely ok with being tested

When Ahab saw Elijah, he said to him, “Is it really you, the one who brings disaster on Israel?” Elijah replied, “I have not brought disaster on Israel. But you and your father’s dynasty have, by abandoning the Lord’s commandments and following the Baals. Now send out messengers and assemble all Israel before me at Mount Carmel, as well as the 450 prophets of Baal and 400 prophets of Asherah whom Jezebel supports. 
Ahab sent messengers to all the Israelites and had the prophets assemble at Mount Carmel. Elijah approached all the people and said, “How long are you going to be paralyzed by indecision? If the Lord is the true God, then follow him, but if Baal is, follow him!” But the people did not say a word. Elijah said to them: “I am the only prophet of the Lord who is left, but there are 450 prophets of Baal. Let them bring us two bulls. Let them choose one of the bulls for themselves, cut it up into pieces, and place it on the wood. But they must not set it on fire. I will do the same to the other bull and place it on the wood. But I will not set it on fire. Then you will invoke the name of your god, and I will invoke the name of the Lord. The god who responds with fire will demonstrate that he is the true God.” All the people responded, “This will be a fair test.”
1 Kings 18:17-24 NET

Ok, so it's not exactly a randomized, double-blind, controlled trial, but it is a pretty clear example of God being put to the test and demonstrating the effectiveness of Elijah's prayer for fire (and later rain).

The prophets of Baal tried everything they could think of, but were unable to cause the sacrifice to catch fire. Afterwards Elijah had some people pour water over the sacrifice, then prayed, and suddenly fire "fell from the sky" and consumed the sacrifice.

As an aside, I am very skeptical of the historicity of this event, but all the same it does sound a lot like a lightning strike, and they were on a mountain, and water is a good conductor (there were also apparently natural springs nearby, which would explain where they found 12 jugs worth of water in the middle of a drought).

There's a lot more I could say about this contest, such as the fact that both Yahweh and Baal were considered "storm deities" who could control the wind, rain and storms (hence why this contest is such a big deal in the story), but I want to focus on another aspect.

When Baal failed to produce fire, Elijah began doing what could only be described as heckling from the sidelines. He offered the following suggestions for why Baal might not be up to the task.
"Yell louder! After all, he is a god; he may be deep in thought, or perhaps he stepped out for a moment or has taken a trip. Perhaps he is sleeping and needs to be awakened."
1 Kings 18:17 NET


It's interesting that Elijah said, "After all, he is a god", referring to Baal. I wonder what he meant by that?

Intercessory Prayer

I searched on Google Scholar for studies on Intercessory Prayer (sometimes referred to as IP) and I came across several that I found very interesting. Two of them showed a statistically significant positive benefit in favour of prayer, with one of those showing that patients who had been prayed for suffered roughly 10% fewer complications on average than those in the control group. There was no significant difference in the duration of the hospital visits between the two groups.
The IP group subsequently had a significantly lower severity score based on the hospital course after entry (P less than .01). Multivariant analysis separated the groups on the basis of the outcome variables (P less than .0001). The control patients required ventilatory assistance, antibiotics, and diuretics more frequently than patients in the IP group. These data suggest that intercessory prayer to the Judeo-Christian God has a beneficial therapeutic effect in patients admitted to a CCU.
Abstract (Byrd 1988) 

Using a severity-adjusted outcomes score, we found lower overall adverse outcomes for CCU patients randomized to the prayer group compared with those randomized to the usual care group. Lengths of CCU stay and hospital stay after initiation of prayer were not affected. These findings are consistent with those of Byrd, who reported that intercessory prayer for hospitalized patients lowered the hospital course score but did not significantly affect length of stay.
Abstract (Harris, 1999)

However, more recent larger studies showed that prayer had no significant effect on complications or recovery time.
As delivered in this study, intercessory prayer had no significant effect on medical outcomes after hospitalization in a coronary care unit.
Abstract (Aviles, 2001) 

Intercessory prayer itself had no effect on complication-free recovery from CABG, but certainty of receiving intercessory prayer was associated with a higher incidence of complications.
Abstract (Benson, 2006)

It is interesting to note that in this last one, which was titled "Study of the Therapeutic Effects of Intercessory Prayer (STEP) in cardiac bypass patients", those who were prayed for suffered more complications than those who were not, with a statistically significant result. The authors suggested that result may be due to "chance", something they were pulled up on in a follow-up paper. Imagine the backlash if they had put a positive result down to "chance"! This follow-up paper offers the following suggestion instead, which sounds more reasonable to me:
A more straightforward interpretation might have been that patients who were asked to hide a clinical study treatment assignment from their bedside staff and “who were certain that intercessors would pray for them had a higher rate of complications,” that is, that this construct appears to do harm.
Full Text (Krukoff, 2006)

So what should we make of this? At this point, it all looks uncertain. The results are not very clear. Perhaps some studies had flaws, whether in their methodology or their results, but if so we don't know which ones. There were several corrections made to the 1999 study by Harris et. al., but as far as I can tell they did not affect the conclusions to any large degree. Further, if there is some positive correlation between intercessory prayer and recovery outcomes, it is very weak. Perhaps God can (or will) only do so much...

This kind of uncertainty is not all that uncommon in science, particularly in studies relating to measures of illness or well-being. A single study might conflict with another one, and it might take several more studies, perhaps with even stricter controls, to really get at the underlying truth. That's why it's also important to look at the overall trends, and that is what review studies try to do as well. Of course, these might still contain subtle errors, but over time we will start to see results. If studies did continue to produce mixed results, then that says something as well.

In this case we do have one such review study, which included all of the studies listed above and at least six more that I didn't mention.

Here is the conclusion given by that review:
These findings are equivocal and, although some of the results of individual studies suggest a positive effect of intercessory prayer, the majority do not and the evidence does not support a recommendation either in favour or against the use of intercessory prayer.
Abstract (Roberts, 2009)

And further down in their longer "plain language summary":
(Note that the word "significantly" refers to statistical significance, which may actually be slight, rather than the colloquial meaning of the word)
Overall, there was no significant difference in recovery from illness or death between those prayed for and those not prayed for. In the trials that measured post-operative or other complications, indeterminate and bad outcomes, or readmission to hospital, no significant differences between groups were also found. Specific complications (cardiac arrest, major surgery before discharge, need for a monitoring catheter in the heart) were significantly more likely to occur among those in the group not receiving prayer. Finally, when comparing those who knew about being prayed for with those who did not, there were fewer post-operative complications in those who had no knowledge of being prayed for. 
The authors conclude that due to various limitations in the trials included in this review (such as unclear randomising procedures and the reporting of many different outcomes and illnesses) it is only possible to state that intercessory prayer is neither significantly beneficial nor harmful for those who are sick.
Full Text (Roberts, 2009)

That is certainly not an encouraging result for those who strongly believe that prayer is effective. Many apologists have claimed that these studies are flawed for various reasons (God cannot be tested, the conditions were not favourable etc), but it seems to me that the biblical evidence, especially the "contest on Mt Carmel" contradicts these reasons. Many of these same excuses could have been argued just as effectively by the prophets of Baal, could they not?

Other implications

What if these studies were somehow bogus and prayer really did work effectively and reliably? What would that actually mean?

Well, the first thing it would mean is that either no one is praying for the millions of people around the world who are suffering from countless diseases and disasters, or God is not interested in helping them. That latter option would suggest that literally every charity is ironically attempting to work against the will of God by helping people he already chose not to help. Some will argue that God works through charities, but the unavoidable conclusion of that argument is that God intentionally uses less effective methods to save people knowing that more will die that way than if he had saved them directly. That sounds rather malicious to me...

The second thing it would mean is that either God can change his mind in response to prayer (which would mean he does not know the future), or God already knew you were going to pray and thus your prayer did not actually result in any change from what God already knew he would do. In this latter view, either you had no choice (i.e. no free will) but to pray, or your prayer was redundant. But if you say your prayer was redundant, then that means prayer is ineffective. Back to square one.

The third thing it would mean is that God is either unaware of the suffering of millions of people around the world (which would mean he is not all-knowing), or he is aware but chooses not to help them unless (and until) someone he likes prays for them (or they pray for themselves). Is a single prayer enough? Why then do so many people, including Christians and Christadelphians, still suffer?

The last thing I will mention here is that some believers seem to think God either inflicts or allows suffering either as a test of faith or so that people will turn to him for help. This is one of the most harmful ideas ever to be embraced by Christianity, as it can lead to a feeling of helplessness - where a person doesn't try to improve the situation (even if they could) because they believe it was intended by God.

Further, just like an abused spouse, the believer attempts to rationalise the constant testing and abuse as a sign of love:
And have you forgotten the exhortation addressed to you as sons? “My son, do not scorn the Lord’s discipline or give up when he corrects you. “For the Lord disciplines the one he loves and chastises every son he accepts.” Endure your suffering as discipline; God is treating you as sons.
Hebrews 12:5-7 NET

He hurts you because he loves you. Sound familiar?


The evidence I have presented strongly suggests that intercessory prayer has not been demonstrated to be effective, at least in the vast majority of cases. If it was effective, hospitals would employ faith healers instead of doctors. Scientific studies have demonstrated conclusively that modern medicine is far more effective than faith healing.

I find it strange that so many people believe so strongly in prayer when the evidence around them is so weak, if not non-existent. Many believers seem to think that prayer cannot (and should not) be tested, which allows them to go on believing while ignoring all of the contrary evidence around them. Further, to question the effectiveness of prayer is perhaps seen as questioning God, which is another taboo deeply held by most believers.

There is clearly some cognitive dissonance involved in believing in the effectiveness of prayer while accepting that so many people still suffer and die at the same rate regardless of whether they pray and/or are prayed for. Perhaps this dissonance is resolved by adopting the belief that one should not question God's priorities, and assuming that God has some perfectly valid, yet unknown-to-us, reason for not helping us. Perhaps God only works in situations where his input cannot be measured. How convenient! If so, God's existence becomes indistinguishable from his non-existence, which should make all of us very suspicious. This is exactly the kind of thing Occam's Razor is for.

So why have all our attempts to prove the effectiveness of intercessory prayer failed? Well, Elijah might be able to offer some helpful advice...

Yell louder! After all, he is a god; he may be deep in thought, or perhaps he stepped out for a moment or has taken a trip. Perhaps he is sleeping and needs to be awakened.

The irony.


  1. Most Christadelphians, even if of an enquiring frame of mind, would shy away from questioning God. "What will God think of me?" they would think to themselves. they should read and think about your section "Can God be tested?"

  2. I seem to recall a special prayer request that was circulated around UK ecclesias several years ago, urging all ecclesias, on a particular Sunday, to offer up special prayers to hasten the coming of Jesus. I didn't understand the point of this. If no one knows the day or the hour, how is prayer going to bring Jesus back any sooner? Were we trying to change God's mind and get him to bring his plans forward?

  3. My memory is of brethren praying for all sorts of things, including asking for a fair weather condition on the day of an ecclesial event. And frequently in a concluding prayer the request was that God should "Hasten the day of the return of our Lord".

    1. Prayers relating to the weather amused me because the idea of praying for rain just felt like a relic from a bygone age. We know how the hydrological cycle works. If there's a god sitting up there moving clouds around or manipulating high/low pressure systems, he's doing it the hard way (and he has some weird priorities and many things to answer for).

    2. Except that meteorology is still an inexact science, and the weather is very hard to predict with accuracy (British weather in particular being legendary in this regard). Unpredictability and the resulting uncertainty is part of the reason why people pray. You don't pray for the sun to rise tomorrow because you know it will - but praying for rain might be worth it.

      There's something very comfortable and smug about praying for nice weather for your ecclesial outing, when there are people in other countries dying from the effects of drought. If you're asking God to move the rain clouds a little bit so you can have nice weather for your picnic, why not ask him to move them a little further to bring rain on a part of Africa that hasn't had a harvest for two years?

      I'm not sure if this kind of thing says something about the priorities/awareness of the person praying, or a feeling that you shouldn't ask for too much.

      When I was a believer, I was careful about what I prayed for. I knew there was no point praying for world peace, for example. I carefully chose smaller things that I thought had a chance of being fulfilled: the success of relief efforts for a particular disaster, for example. Or I would pray for something fairly unmeasurable, like "Please help so-and-so through this difficult time". This kind of strategy does tend to lead to 'confirmation' that your prayers work.

    3. I used to do the opposite with prayers. I tried to ask for things that had a low probability of occurring by chance, so that if they were "answered" I could have greater confidence that God was behind it (or so I thought). For some reason I felt that the less likely something was to happen by chance, the more likely it was a miracle. The logic is obviously flawed, but that didn't bother me. Anyway, God apparently chooses to only answer prayers at exactly the rate of blind chance, presumably to remain undetectable and thus uphold the faith requirement. Clever. Or non-existent. It's so hard to tell.

      It reminds me of a joke by comedian Steven Wright: "Last night somebody broke into my apartment and replaced everything with exact duplicates"

      This is the game that believers are playing when it comes to belief in God and prayer. If the prayer is answered, God is real! But if it isn't, he's still real but chose not to answer. They never say what we'd expect to see if he wasn't real...

    4. Reminds me of a cute saying I once heard: "God always answers prayer, but sometimes the answer is No."

      Sorry, but that's just playing with semantics...

    5. I thought the classic formulation was: God always answers, but it may be Yes, No, or Wait.

      Adding "Wait" to it softens it a bit (it's not a slap in the face and rejection of everything you're asking, it's just that you should have a little patience). It also makes it much more likely to be fulfilled. For example, if you ask for things to get better in your life generally or a particular problem to be overcome, it won't be that surprising if things improve in the next few years. And that was obviously the will of God for your life, that you should learn a little patience (you have heard of the suffering of Job, etc.) When things are then going well, it's quite easy to produce a post hoc rationalisation of why this was the best possible time for God to act, so people speak of their faith being strengthened by these alleged "Wait" answers.

      Now I never interpreted prayers that way, and I'm not quite sure why (I heard it often enough). I'd like to say it was because I saw the problems with the vagueness of the prayers and the alleged fulfillments, and maybe it was, but I think it was more that I was independent enough that I didn't really want to be reliant on other people, or on God. Maybe I was one of those people that God needed to break so they could learn to rely on him - but I don't believe he ever did...

  4. Prayers were called for when a brother was ill. The consultant transferred him from one hospital to another hospital where a sister happened to work.This was loudly claimed as being a positive answer to prayer. Within 24 hours he was moved to another hospital, then a third, then he died. No attempt was made to see the hand of God in the apparently reversed decision this time.
    Beliefs are so strongly held (because of from-the-cradle indoctrination mainly), that it is accepted that they are without question, that it is wrong to so do. The bible is God`s word. God exists. He will hear my prayer. No question. So nothing belief-wise is questioned or examined as to its veracity.
    Blindfold acceptance doesn`t lead anywhere, even to sensible "we don`t know" thinking.


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