Meditation has been shown scientifically to increase or improve:

1)Intelligence(figural reasoning, adaptability, creativity & comprehension) (University of Leiden)
2) Inner-directedness (Journal of Counselling Psychology)
3) Time competence (Journal of Counselling Psychology)
4) The holding of values of the self-actualised state (Journal of Counselling Psychology)
5) Spontaneity (Journal of Counselling Psychology)
6) Sensitivity to own needs (Journal of Counselling Psychology)
7) Self-acceptance (Journal of Counselling Psychology)
8) Capacity for warm interpersonal relationships (Journal of Counselling Psychology)
9) Flexibility in application of values (Journal of Counselling Psychology)
10) Self-regard (Journal of Counselling Psychology)
11) Tolerance to aggression (Journal of Counselling Psychology)
12) Fluency, flexibility and originality of creativity (California State University)
13) Job satisfaction (Academy of Management Journal)
14) Job productivity & performance (Academy of Management Journal)
15) Relations with supervisions (Academy of Management Journal)
16) Relations with co-workers (Academy of Management Journal)
17) Internal locus of control (U.S.A. 1974)
18) Learning ability(University of California)
19) Efficiency of solving arithmetic problems(University of Alberta)
20) Mental effectiveness
21) Reaction time (University of Texas)
22) Low blood pressure
23) Superior perceptual-motor performance (University of California)
24) Autonomic stability (measured by skin resistance response) (Psychosomatic Medicine)
25) Relief from insomnia
26) Effective interaction with the environment (Psychosomatic Medicine)
27) Faster recovery from sleep deprivation (University of Alberta)
28) Broader comprehension & improved ability to focus attention (University of California School of Medicine)
30) Self-actualisation (Journal of Humanistic Psychology)
31) Development of personality (Journal of Counselling Psychology)
32) Physiological rehabilitation of prisoners (La Tuna Federal Penitentiary)
33) Psychological rehabilitation of prisoners (University of Texas)
34) Tolerance (York University)
35) Short & long term memory recall (University of California)
36) Organization of memory (University of Alberta)
37) Academic performance (Washington, D.C)
38) Speed of success within organisational structure (Academy of Management Journal)
39) Exponential magnification of management performance (Academy of Management Journal)
40) Speed of solving problems accurately
41) Energy levels
42)Cordiality
43) Good Humour
44) Ecological adaptability
45) Metabolic stability
46) Biochemical stability (American Journal of Physiology)
47) Electrophysiological stability
48) Interhemispheric neurological balance
49) Cardiovascular efficiency (University of California)
49) Respiratory efficiency
50) Recovery from exertion
51) Emotional stability
52) Improved resistance to disease 
3) Normalisation of weight
54) Self-confidence
55) Stability of attention
56) Self-esteem
57)Perceptual ability (University of Victoria, B.C.)
58) Field independence (University of California School of Medicine)
59)Restful alertness/wakefulness(France 1974)
60)Near point vision (UCLA)
61) Hearing Threshold (UCLA)
 

Meditation has also shown to decrease:

1) Desire to change jobs (Academy of Management Journal)
2) Promotion fixation (Academy of Management Journal)
3) Anxiety (Harvard University)
4) External locus of control (U.S.A 1974)
5) Drug use & abuse (Congressional Record, Washington, D.C.)
6) Alcohol and cigarettes consumption (Congressional Record, Washington D.C.)
7) High blood pressure (Journal of Psychosomatic Medicine)
8) Bronchial asthma (University of Colorado-Medical Centre)
9) Oxygen consumption (University of California)
10) Social rigidity
11) Social inadequacy
12) Social introversion
13) Antisocial behaviour
14) Irritability
15) Depression
16) Neurosis
17) Blood lactate (Scientific American)
18) Insomnia (University of Alberta)
19) Crime rate (at 1% meditator population over 12 United States cities)
20)Hospital Admissions/doctor visitation (50% less)
21) Heart disease (80% less)
22) Cancer (50% less)