I think some few people here might be doing a conceptual mistake; Ti alone does not deal with any data at all. TP, or Thinking-Perceiving, does (that is one of the few differences between TP and Ti, these are hard to spot and some people might confuse TP and Ti because they are the same in a lot of points, but not all of them). Ti is an introverted function, its oriented through internal psyche, while Te as an extroverted function is oriented by external and environment. Ti does not gather data because there is no data for internal psyche, mostly (I dont know if we could count our own personality tests results as data for internal psyche, perhaps).
However, people forget that cognitive function by themselves doesnt actually do that much and it is kind of rare to find them on a really pure form. Instead, in a lot of times they work together, and not only necessarily on pairs or with the "thought trains" are presented out there, but in a way more free way.
Ti can be combined and used in data analysis, Ti can be used to make sense of data that it is presented. For example, to figure out how a machine works, maps and schemes might be drawn; Depending on the complexity, these draws will come and be gathered/perceived from Se or Ne or both. Then Ti can be used to make sense of the map and how it works using its own logic, so the map scheme reading and all stuff we see in a lot of websites related to Ti relies on Ne and Se. Ne and Se perceives the data; Ne connects the dots; Ti is used to make sense in what are we reading and drawing dynamics. Sometimes, we might even go back and forth between the functions.
When we talk about data, although, it might be discussable if Se or Ne does the job. In my opinion, it is still pretty much Te works. While Te might be used for data orientation and to gather data, Ti can be used to make sense of that data, Ne can go in to make connections and dots between data (yep, a Te-Ne combo), and the process can go back and forth a lot of times (gather, connect, make sense, gather, make sense, connect, etc... In a lot of different orders).
Just as an extra: Te can back up a lot of functions in a supportive way, although in non-essential (while Ti can do the same). Te-data can be used to back and support Ti logic systems, to give them validation and to ground them more on reality (although this latter is more Se related), can be used to support Ne connections, can be use as a support for Fe values, I have been creatively using it to track Fi primordial values (although I do think that is kind of an impure support), well, it can be combined with almost all cognitive functions (although I think combining Te with Fe and Fi might be problematic). Ti-logic can be used to make sense of Se and Ne stuff, to detect something wrong with data gathered by Te (data is not matching expected dynamics), I dont see much use on Si but I wouldnt be surprised if someone figure how, Ti can be used to make some sense of Fi values and to help make sense of Ni-insights, although Fi can do completely fine without that, and I dont think see much good ways to mix Ti and Fe.
This is a valid question; The way that I phrased this, looking back, does very much apply to both Ji functions to a degree (and I have seen both illogical and logical Fi users do this as well; I hyper generalized my description). I didn't really take the value thing into account because I briefly forgot that existed. It very much comes down to the bolded, they cannot tie it back to what they already know or have gathered. Logical high Fi often also strongly values being separate from the external, more in regards to their values and self/individualism than in systems because they are very much connected to these things.
As a personal example of illogical Ti (ie. myself being an idiot and low Ti), there was a point in my chemistry class that I literally could not remember certain pieces of information not because I couldn't understand them, but because they completely contradicted everything I knew about the subject prior to learning about these things (despite those specific pieces of information being semi-proven to be correct and commonplace in textbooks). Until I went back and rationalized how those pieces of information fit into the concept I had built of the subject (and by extension, readjust my system of understanding), I literally continued to discard the information unconsciously because "this piece of information was obviously some sort of misconception, there had to be something more correct."
I'm not sure this is helpful. If this still sounds Fi-esque, I could just be wrong, lmk. I'm still in the process of reorienting myself with mbti definitions, so if it's off my definitions could just be off.
Cognitive function skills and preferences are entirely different things.
Being a Ti-tard and scoring low on Ti on cognitive function means that the person is not using Ti much (since that is directly the interpretation of the person marking "not me" on Ti questions). If a person doesnt use Ti much, that does not necessarily means that a person is bad at using Ti. This field is quite unexplored, but as far as I know the best speculation is that Ti and Te good or bad use are a lot influenced by Ne and a little bit by Ni use. I say that because Ti and Te relies somewhat on IQ, and IQ has been, by research, somewhat predicted by intuition dimension on dichotomy (and a little bit on Perceiving, Thinking and Introversion). IQ tests uses a lot of abstract stuff, and abstract stuff is related to Intuition on MBTI, which means that the competency of Ne and a little bit of Ni does influence Ti and Te use.
Connecting piece of information is Ne related, making sense of the whole is basically a Ti and Ne combo.
Actually, Ti-Ne or Ne-Ti does even form some sort of studying tactics on their own. Its basically switching back and forth between conceptualizing and doing mind maps and connections, and, on a very meshed way, to make conceptualized connections. Thats pretty much the NTP recipe for studying, and it is one that NFPs can also take advantage of and perhaps STPs too. Also, Jung directly pointed out that memorization has nothing to do with the functions (even some posts of mine relates memorization to Si). I never saw any study between long-term memorization capacity and MBTI types.
But wait... I dont remember you [MENTION=34313]RadicalDoubt[/MENTION] being bad at using Ti.
And wait... ISFJ? Where that came from?
Well, that is already off-topic although.