Religious belief is beneficial to the individual
Many websites feature personal accounts of how lives were positively changed by converting to a particular religion. This is a form of the argument from personal experience. This argument is sometimes referred to as the argument from a wonderful life or Jesus transforms lives.
- "How do you explain the radically changed lives of so many Christian believers down through history? "
"Down through history Christians have found through Jesus a personal acquaintance with God that has transformed their lives."
- "It is claimed that if someone adopts the new religion, there will be positive changes in the person’s life and state of well-being. "
- "Fine feelings, new insights, greater interest in 'religion' mean nothing unless they make our actual behavior better [...] In that sense the outer world is quite right to judge Christianity by its results. [...] Our careless lives set the outer world talking; and we given them grounds for talking in a way that throws doubt on the truth of Christianity itself."
Anecdotal accounts of religious conversion suggest a significant change in a person, which should be observable. Major denominations claim to have tens of thousands of converts every year. 
- Main Article: Religious belief has psychological benefits
- "If you're struggling to overcome an addiction, the good news is you can do it with God's help. "
- Main Article: Prosperity gospel
- "The results of the meta-analysis show that religious beliefs and behaviors exert a moderate deterrent effect on individuals' criminal behavior. "
Lower crime is probably explainable by natural causes, such as the belief in a heavenly watcher causing people to moderate their actions.
Researchers note that behaviour and values are modified after a religious conversion but they include participation in religious rituals as a behaviour change and is not necessarily reflective of an improvement in moral conduct. There is actually many shortcomings with existing research but the large effect in moral conduct claimed by religion has not yet been observed.
The difference in moral conduct between believers in a religion and those of other religions or atheists is limited to values, goals and identity. This is also explainable by natural causes. The underlying personality of a convert remains unchanged. According to the grand claims of religion, we should see a significant moral and personality transformation in converts.
- "[conversion] can result in profound, life transforming changes in mid-level functions such as goals, feelings, attitudes, and behaviors, and in the more self-defining personality functions such as identity and life meaning. [...] However, most of the research is retrospective and cross-sectional, and no systematic program of research has ever been sustained. [...] the popular claims of dramatic changes in basic personality structure, by both those opposed to new religions as well as those who see them in more positive terms, do not seem to be warranted by the evidence. [...] conversion seems to have minimal effect on elemental functions such as the Big Five traits "
This is largely explained by the placebo effect and other factors in human psychology.
- "People have inner resources on which they draw, often without knowing how they are doing it or even that they are doing it. [...] These epiphanies seem to announce themselves to us, as if they came from an external guide: another example of the Projection Fallacy. "
Argument from ignorance
Many Christians are not sincere
- "If conversion to Christianity makes no improvement in a man's outward actions-if he continues to be just as snobbish or spiteful or envious or ambitious as he was before-then I think we must suspect that his 'conversion' was largely imaginary "
This is the no true Scotsman fallacy.
Christianity attracts people more in need of help
- "There is even, when you come to think it over, a reason why nasty people might be expectred to turn to Christ in greater numbers than nice ones. [...] Christ said 'Blessed are the poor' and 'How hard it is for the rich to enter the Kingdom' [...] But do not His words also apply to another kind of riches and poverty? [...] If you have sound nerves and intelligence and health and popularity and a good upbringing, you are likely to be quite satisfied with your character as it is. 'Why drag God into it?' you may ask. [...] If you are a nice person-if virtue comes easily to you-beware!"
This can be handled by longitudinal cohort studies to avoid sample bias.
You can't just compare two people
- "Christian Miss Bates may have an unkinder tongue than unbelieving Dick Firkin. That, by itself, does not tell us whether Christianity works."
This can be handled by using larger sample sizes.
- ↑ 
- ↑ 
- ↑ 3.0 3.1 3.2 Raymond F. Paloutzian, James T. Richardson and Lewis R. Rambo, Religious Conversion and Personality Change, Volume 67, Issue 6, pages 1047–1079, December 1999
- ↑ 
- ↑ Baier and Wright, “If You Love Me, Keep My Commandments”: A Meta-Analysis of the Effect of Religion on Crime, Journal of Research in Crime and Delinquency February 2001 vol. 38 no. 1 3-21
- ↑ Rebecca Newberger Goldstein, 36 Arguments for the Existence of God: A Work of Fiction, 2011
- ↑ 7.0 7.1 7.2 C.S. Lewis, Mere Christianity