DAT Harder/Easier: DEBUNKING A MYTH!

Discussion in 'DAT Discussions' started by doc toothache, Apr 14, 2007.

  1. doc toothache

    10+ Year Member

    Joined:
    Jan 17, 2006
    Messages:
    8,027
    Likes Received:
    2,168
    Status:
    Dentist
    There have been a number of posts on SDN regarding the degree of difficulty of the DAT exam. Most are convinced that the DAT has gotten much harder. A few believe that the degree of difficulty has not changed.

    DAT Hard or Easy? Harder or Easier?

    The DAT is both hard and easy. It is hard for those who do not do well and it is easy for those who do well. To substantiate the claim that the DAT is harder, there are those who profess to have taken it a second time and promptly declare it to have been harder. In this case, the more appropriate phrase should be: "I just retook the DAT and it was harder" for me. Some have friends who took the DAT for the second time and give a similar verdict. There is no doubt that for those that didn't do as well the second time around, the exam was indeed harder.

    A Case of Misinformation/Misinterpretation

    Many posts have been alarmed by the perceived dramatic increase in the DAT scores. One post suggested that the bio score has changed from 17 to 20. Another post suggested that the DAT test has been purposely made harder because of an overabundance of high scores (24-25). Still another (apparently based on insider info) pinpointed the change to a harder DAT to have started in the spring. One agitated OP was ready to call in the National Guard since she believed copies of the DAT exams were out and were made available to a select few of her classmates. Someone else believes that there are only a few versions (4-5) of the DAT exam.

    Statistical Evidence

    Published statistical data supports the fact that the DAT scores have remained relatively unchanged for both the applicant and enrollee pool. (1) (See Table) For the applicant pool, the AA scores ranged from a low of 17.2 (1999) to a high of 18.0 (2001/02). The PA scores ranged from a low of 16.5 (1998/09) to a high of 17.8 (2003/04). For the enrollee pool, the AA scores ranged from a low of 18.1 (1999) to a high of 19.3 (2006). The PA scores ranged from 17.1 (1999) to 18.4 (2006).(2) The DAT is a standardized test. The purpose of a standardized test is to have results that can be compared between students and from year to year. The results can be documented to have a relative degree of validity and reliability. The results can be generalized and replicated. We may want to think of the DAT using a chemistry analogy. The DAT is a buffer (buffered solution) where the mean scores (pH) remains relatively unchanged by addition of high or low scores (acid or base).

    Scores of 24 and Above

    The table shows the percentile distribution of scores of 24 and above for various sections of the DAT. (3) For the period from January 2006 to June 2006 (4), the frequencies are, admittedly, higher than expected. It remains to be seen whether or not they will stay at this level when all of the 2006 figures are taken into account. For this period, only 2600 candidates took the test, a figure which is a far cry from the ~12 K expected to have taken the test. Whether or not the percentage of scores of 24 above increases dramatically is not going to be particularly significant. The increase would be of significance only if it had an impact on the mean. This is unlikely to happen.

    Number of DAT versions.

    In all likelihood, only a limited number of ADA staff knows the number of versions that are available. However, it is inconceivable that an organization such as the ADA, with all the resources at its disposal, cannot come up with virtually an endless number of versions. If, for general chemistry alone, Schaum's can come up with close to 3000 questions for the Solved Problems Series and over 1100 questions for the Schaum's Outlines, surely the DAT come up with more than a few versions of the exam.

    ADA will make the DAT harder.

    It is a mystery why ADA would need to make the DAT harder. While the frequency distribution of some sections of the DAT may fluctuate from year to year, AA scores are less likely to fluctuate. Making an argument for the ADA supporting making the DAT harder is an unenviable task. Keep in mind that for TS each missed questions up to 6 decreases the STD score by a point each. (5) For a score of 24 in TS, a candidate only missed 6 questions. If the ADA wanted to bring the mean down, it could easily do so by changing the range of correct answers needed for a mean of 17 or 18.

    Applicants/Enrollees Pool.

    There seems to be some confusion regarding which DAT scores are under consideration. As it has been pointed out in a previous post, a distinction needs to be made between the applicant pool and the enrollee pool scores. The applicant pool mean scores are generally lower than that of the enrollee pool. As the number of applicants increases there will be an increase in the number of applicants that have scores above the mean. The net effect of choosing candidates with higher scores will be a shift of the mean to the right, or if you will, an increase in the mean scores for enrollees. In order to reach an AA mean of 20 for enrollees, the applicant pool would have to be ~25K.
    Code:
    	  
    		Applicant Pool		Enrolee Pool	
    Year		AA	PA	AA	PA
    1998		17.3	16.5	18.2	17.2
    1999		17.2	16.5	18.1	17.1
    2000		17.8	17.1	18.5	17.7
    2001		18	17.6	18.8	18.1
    2002		18	17.7	18.8	18.1
    2003		17.8	17.3	18.5	17.5
    2004		17.8	16.7	18.7	17.3
    2005		17.7	16.7	18.9	17.4
    2006		17.97	17.46	19.29	18.45
    
    
    		Scores at 24 and above	(Percentage)				
    									
    Year	Count	QR	RC	Biology	G. Chem	O Chem	TS	AA	PA
    1988	2631	0.3	2.5	0.4	0.9	1.2	0.4	0.1	0.8
    1994	9323	2.11	2.7	0.7	3.1	3.4	0.5	0.4	0.4
    1999	6645	3	8.1	2.3	4.8	5.8	1.2	1.3	0.8
    2004	11363	2.5	7.1	1.2	4.3	4.6	1.5	1.1	0.2
    06 pre  2600	4.4	8.5	2.4	5.5	8	2.5	0.9	1.4
    
    				Dental Admission Test					
    				Standard Score Analysis					
    				2004					
    
    
    			                 # of Items	Mean	S.D.				
    
    Quantitative Reasoning			40	16.31	3.22				
    Reading Comprehension			50	18.89	3.05				
    Biology			                40	17.24	2.64				
    General Chemistry			30	17.15	3.47				
    Organic Chemistry			30	16.99	3.71				
    Survey of Natural Sciences	       100	17.12	2.68				
    Perceptional Ability			75	16.35	2.44				
    					
    										
    			
    
    								
    


    (1) R. Weaver, U.S. Dental School Applicants and Enrollees: A Ten Year Perspective, J. Dent Educ. 2000 Sep; 64(12): 867-874.
    (2) R. Weaver, U.S. Dental School Applicants and Enrollees: 2003-2004, J. Dent Educ. Sept 2005:69(9):1064-72.
    (3) www.ada.org/prof/ed/testing/dat/dat_users_manual.pdf
    (4) www.ada.org/prof/ed/testing/dat/dat_score_frequency.pdf
    (5) www.ada.org/prof/ed/testing/dat/dat_estimate_score.pdf
     
  2. Note: SDN Members do not see this ad.

  3. ddstobe

    5+ Year Member

    Joined:
    Nov 30, 2006
    Messages:
    415
    Likes Received:
    0
    :eek: :eek: :eek: OMG, how many hrs had you spent on writing this report? May I ask you to come up with a new report w/ some real DAT questions?:p
     
  4. BodybldgDoc

    BodybldgDoc Guest

    Joined:
    Jan 13, 2007
    Messages:
    712
    Likes Received:
    0
    Status:
    Pre-Health (Field Undecided)
  5. jdmsamurai

    2+ Year Member

    Joined:
    Feb 11, 2007
    Messages:
    237
    Likes Received:
    1
    Status:
    Dental Student
  6. l2suture

    2+ Year Member

    Joined:
    Sep 11, 2006
    Messages:
    15
    Likes Received:
    0
    Status:
    Pre-Dental
    The DAT is a buffer (buffered solution) where the mean scores (pH) remains relatively unchanged by addition of high or low scores (acid or base).

    The best analogy I've ever heard in my life and on SDN. A great mix for Chem/Pre-dental students such as myself. =)
     
  7. Drill2Fill

    Drill2Fill DentalStudentWannabe
    5+ Year Member

    Joined:
    Mar 20, 2006
    Messages:
    1,097
    Likes Received:
    1
    Status:
    Pre-Dental
    wow. Good work!
     
  8. styler5555

    2+ Year Member

    Joined:
    Dec 19, 2006
    Messages:
    16
    Likes Received:
    0
    Status:
    Pre-Dental
    those statistics, of 2600 test takers, apply only to first-time DAT takers....
    i'm not trying to dispute your claims...just to highlight that point and also point out that most people complaining of the DAT (on this site anyways) being harder were taking the test for the second time....


    A harder DAT is only relevant to scale it uses to grade test takers. A much harder test, after months of students performing lower than expected, should hypothetically shift the curve around....so long as, the average/distribution are within a statistical range....it will balance itself out at the end of the day.
     
  9. ATLATLATL

    2+ Year Member

    Joined:
    Jan 9, 2007
    Messages:
    113
    Likes Received:
    0
    Status:
    Pre-Dental
    fingers crossed...hehe
     
  10. danbarr

    2+ Year Member

    Joined:
    Sep 10, 2006
    Messages:
    67
    Likes Received:
    0
    Status:
    Non-Student
  11. doc toothache

    10+ Year Member

    Joined:
    Jan 17, 2006
    Messages:
    8,027
    Likes Received:
    2,168
    Status:
    Dentist
    Which part is:confused: ing you?



    There was no explanation from the ADA as to why in the Frequency Tables for Jan to June 2006 was limited to only those who took the test for the first time. In any case, it has little relevance. Incidentally the scores for this period were higher rather than lower than expected. The ADA is not going to get excited about the scores (high or low) every time someone finishes the test at a Prometric Center. Why not you might ask? ADA understands statistics and knows that the Jan to June results are not representative of the population (for the year) because this is not a randomly selected sample of the population. If they were concerned, they could get a better picture by doing a random sample from the 2600 candidates that took the test. About 30% of the candidates taking the DAT are repeats. You can bet the farm that ADA is not making the test harder or easier based upon any given batch.

    Code:
                   DAT Repeat Exams Analysis 2004		
    
    	Exam initially taken in 2004 		7984	70.26%
    	1st time repeat		                2365	20.81%
    	2nd time repeat		                 694	6.11%
    	3rd time repeat		                 214	1.88%
    	4th time repeat	                          64	0.56%
    	5th time repeat		                  30	0.26%
    	6th time repeat	                           5	0.04%
    	7th time repeat	                           1    0.01%
    	8th time repeat		                   2	0.02%
    	9th time repeat		                   4	0.04%
           
    		Total	                        11363
     
  12. DDSDakoo

    7+ Year Member

    Joined:
    Feb 27, 2007
    Messages:
    56
    Likes Received:
    0
    FINALLY. :thumbup:

    bad ass you took the time out to do this.

    cheers!
     
  13. PrincessDMD

    PrincessDMD Membership Revoked
    Removed

    Joined:
    Apr 14, 2007
    Messages:
    10
    Likes Received:
    0
    Status:
    Pre-Dental
    Are you saiding that the level of difficult will stay the same, but they will change the # of problems you are allow to miss in order to get a certain score? meaning before you can miss 5 and get a 23 now you can miss only 3 to get the same score?
     
  14. BodybldgDoc

    BodybldgDoc Guest

    Joined:
    Jan 13, 2007
    Messages:
    712
    Likes Received:
    0
    Status:
    Pre-Health (Field Undecided)
    no thats not what hes "saiding"
     
  15. doc toothache

    10+ Year Member

    Joined:
    Jan 17, 2006
    Messages:
    8,027
    Likes Received:
    2,168
    Status:
    Dentist
    You may want to review the paragraph.

    "It is a mystery why the ADA would make the DAT harder............. If the ADA wanted to bring the mean down, it could easily do so by changing the range of correct answers needed for a mean of 17 or 18."

    There is absolutely no evidence to support the contention that the DAT is harder than it used to be irrespective of the circumstances (first timers, etc.) under which it was taken. Circumstantial evidence is not proof of the change. If an exit poll was taken of those that just finished the DAT exam and there was 100% agreement that the exam was hard (er), or for that matter, there was 100% agreement among the 12K that took the test during a given calendar year, the results would remain meaningless. Short of a pronouncement by the ADA, the only possible acceptable proof supporting an argument for a more difficult exam would be to have a significant increase in the mean DAT score during a few consecutive years followed by a decline. This is unlikely to happen. Even with an increase in the frequency of high scores (above 24) the finding would remain irrelevant since more likely there would be a concomitant increase in the frequency at the lower end of scores (below 13).

    For the sake of argument, let us look at a scenario that may bring the mean score to a higher level. Let’s assume that for the dental school class starting in 2008, the top 1% of the approximately 1.5 million students that will be receiving a Bachelor’s degree this May, all decided to pursue a career in dentistry. They merrily take the DAT exam and lo and behold we are seeing mean DAT averages of 22 for the applicants and mean DAT of 23+ for the enrollees. In this scenario, the applicants would certainly be a happy group and the Dean’s of dental school would be jumping with joy. What possible reason would the ADA come up with to make the DAT harder?
     
  16. Buttscratcher

    Buttscratcher Sugar Munster
    2+ Year Member

    Joined:
    Dec 11, 2006
    Messages:
    34
    Likes Received:
    0
    Status:
    Pre-Dental
    Well harder or not...the thought of test day coming near, makes me sick...I want to vomit and cry...just don't know which one to do first.
     
  17. doc toothache

    10+ Year Member

    Joined:
    Jan 17, 2006
    Messages:
    8,027
    Likes Received:
    2,168
    Status:
    Dentist
    While your DAT anxiety may be understandable, should you be accepted to DS you may be in for a rude awakening. What with 22 courses for the first year and 3-5 exams every week (at least for the first semester).....we may be looking at industrial scale quantities of tranquilizers/antiemetics.
     
  18. Mahaveer

    2+ Year Member

    Joined:
    Feb 3, 2007
    Messages:
    28
    Likes Received:
    0
    Status:
    Pre-Dental
    doc toothache give the dude a break...you cannot dental school exams to the DAT...I know both are important but people put 3 months of hard studying into the DAT...its understandable that they get nervous before taking it
     
  19. doc toothache

    10+ Year Member

    Joined:
    Jan 17, 2006
    Messages:
    8,027
    Likes Received:
    2,168
    Status:
    Dentist
    It is not a matter of comparing the DAT with dental school exams. You can rest assured that the anxiety level in dental school is going to be a great deal more intense and for a longer period of time than the the 3 months you may have spent studying for the DAT. You need not worry about getting dispensation from anyone posting on SDN. Dental Schools will far less sympathetic.
     
    #18 doc toothache, Apr 20, 2007
    Last edited: Mar 6, 2012
  20. Mahaveer

    2+ Year Member

    Joined:
    Feb 3, 2007
    Messages:
    28
    Likes Received:
    0
    Status:
    Pre-Dental
    When it comes...we'll all learn to deal with it...until then...just chill
     
  21. dentalwannabee

    dentalwannabee busy bee
    2+ Year Member

    Joined:
    Feb 3, 2007
    Messages:
    125
    Likes Received:
    0
    Status:
    Dental Student
    excellent post! PLEASE MAKE THIS THREAD A STICKY!!!
     
  22. doc toothache

    10+ Year Member

    Joined:
    Jan 17, 2006
    Messages:
    8,027
    Likes Received:
    2,168
    Status:
    Dentist
    Good advice although misdirected.
     
  23. burton117

    burton117 The Big Kahuna
    10+ Year Member

    Joined:
    Jan 7, 2004
    Messages:
    1,087
    Likes Received:
    7
    Great thread - 5 stars!!!
     

Share This Page