Fertility Friend offers four different methods for detecting ovulation: Advanced, Fertility Awareness, Research and OPK/Monitor (see "FertilityFriend.com Interpretation Methods" for more details). Each detector makes use of your own personal cycle data to make interpretations. When your pattern is clear, the detectors will usually provide the same interpretation. Fertility charts, however, as you have probably already noted, are not always perfectly clear.
When charting conditions are not ideal, or when our bodies do not cooperate fully, temperatures may be slightly erratic and the signs may not all correlate perfectly. It is therefore not unusual to have a cycle where the ovulation date is not immediately obvious. Our bodies simply do not always follow textbook rules. To account for this, you will sometimes need an added bit of flexibility in the interpretation to help you find the most likely date. This is why you have several interpretation options. And this is also why we are continuously fine-tuning our advanced and research detectors.
In most cases when there is discrepancy or ambiguity, the advanced detector will give you the best interpretation because it takes all signs into account simultaneously. It also includes tested research gathered from the research detector. The advanced detector is thus the recommended setting and the default for all charts unless you have chosen otherwise in your preferences.
If the chart is so ambiguous that you cannot tell for certain, your best bet for testing purposes is to consider the latest possible ovulation date. This may help you wait for a reliable testing date. If you cannot tell for certain that you have really ovulated, then you may also want to keep on considering that you could be fertile, just to make sure you do not miss an opportunity to conceive. Once the cycle is complete (if you are not pregnant!) you can adjust your chart if needed using your luteal phase length and past cycle statistics, if available, as a guide.
If you use OPKS or a fertility monitor and do not record your temperature: In this case, your best choice for estimating your ovulation day is to use your OPK or fertility monitor results . Although these tests/devices do not give you a full picture of your cycle they can be used for a relatively accurate estimate in most situations. In this case we recommend that you use our OPK/Monitor detector. If you are recording your temperature we recommend against using this detector even if you are using an OPK or a fertility monitor (in this case use the Advanced detector which will use all your data).
For more information, please see: