why such a large variance is stats

[Lassie1982]

looking at stats for % of BFP at X DPO.

And have found that there is a large variance between countdown to pregnancy and Fertility FRiend.
Pregnancy Test Results for 10 Days Past Ovulation | Countdown to Pregnancy (http://www.countdowntopregnancy.com/pregnancy-test/dpo-chart.php?dpo=10)
This says that only 36% of women who are pregnant will get a BFN at 10DPO.
Whilst FF says that at 10DPO only 10% of pregnant charts have a BFN
When can I expect a positive HPT if I am pregnant? (http://www.fertilityfriend.com/Faqs/When-can-I-expect-a-positive-HPT-if-I-am-pregnant.html)

why such a huge variance? which is more reliable?

[bythestream]

I think it is because of the variation in HCG. Some women have high HCG and others lower, it can be different with different pregnancies too. Also cycle length would effect when you get a BFP

The second link is positive tests a 10DPO not sure why their stats don't match up.

[Lassie1982]

I think it is because of the variation in HGC. Some women have high HGC that rises quickly and others take longer, it can be different with different pregnancies too.

See that makes sense, but wouldn't it average out and the stats be similar on each website?
Surely they would both have a diverse range of women and pregnancies.
It's just such a huge difference between the 2 websites.
FF says there is a 10% chance of a Bfp at 10dpo
Countdown says there is a 66% chance.
Both websites use data entered by women, so shouldn't they be similar?


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[Cinss]

Its because on countdown they only factor all the pregnant women. And on FF they factor in everyone.

[Cinss]

So of 10% of the women who get bfps on countdown 66% of THEM get a bfp at 10dpo.

[myGirl]

I see what you're saying Lassie. I would venture to say that people who report bfps on Countdown to Pregnancy are not as precise about dpo. I have looked at many tests there and quite a few ladies will put 9 or 10 dpo but in their comments give away that they are unsure of exact dpo. On FF, they are analyzing charts so they can be sure of dpo.

I would tend to believe FF stats because it takes out the human error factor of women estimating their dpo. As we all know, pinpointing O is difficult even for people who chart and know a lot about it. I think many girls (not all) who post on CTP are more inexperienced in pinpointing O, or don't really care what dpo they fill in as long as they get that photo up so people can guess pos or neg.

Just my opinion.

[BeadinMom]

Doesn't it depend on the type of test you use, too? In my experience, some are more sensitive than others?